The Powerful, The Dominant, The Enforcer.
Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ is Al-Muqtadir (in Arabic: ٱلْمُقْتَدِرُ), the all-powerful who delivers a suitable measure of all things. He has absolute strength, power, and mastery. Nothing is beyond his power.
From the root qaf-dal-ra (ق د ر), which has the following classical Arabic connotations: to measure something, know the measure of something, to distribute, allot or apportion the suitable measure to decree, to ordain, to decide a matter (as though measuring it to fit), to exercise thought in preparing something, to make use of reason, to intend or determine something, to have the power, to accomplish, to be rendered able, to be able to prevail, to be empowered.
Difference between Al-Qadir and Al-Muqtadir:
The names Al-Qadir (The All-Powerful) and Al-Muqtadir (The All-Determiner) both refer to Allah's attribute of possessing power or being capable. But as Imam al-Ghazali mentions, "All-Determiner is more emphatic. Power is equivalent to the intention by which a thing comes into existence according to a determinate plan of will and knowledge, and in conformity with both of them."
So, both names establish Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ as having power, but Al-Muqtadir exercises His power over everything. The example al-Ghazali gives how Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ has determined a day for resurrection. In this sense, He's the All-Determiner, The Enforcer. But if He wished, he could bring about the day of judgment today - but He chooses not to. Everything is done according to His knowledge; the reason for not doing so is up to Him. He's fixed an appointed time, and nothing can resist His plan (similar to Al-Qahhar - the irresistible).
Pairing with the name Al-Malik
Coupling of the name Al-Muqtadir with the name Al-Malik (The King):
Fee maq'adi sidqin 'inda Maleekin Muqtadir
"In a seat of honor near a Sovereign, Perfect in Ability." — (Qur'an 54:55)
What has been said about the pairing of the names Al-Muqtadir and Al-Malik. Imam Zarruq wrote, "Al-Muqtadir comes from iqtidar, which is to overpower whoever He granted a portion of power to. As such, it reverts to the gathering meaning encompassed by the name Al-Malik." It is Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ who has complete and total power. He puts into creation whatever power they possess. No creation by itself is powerful except that Allah has made it such. "If Allah is your helper none can overcome you, and if He withdraw His help from you, who is there who can help you after Him? In Allah let believers put their trust." (Qur'an 3:160)
Wadrib lahum masalal hayaatid dunyaa kamaaa'in anzalnaahu minas samaaa'i fakhtalata bihee nabaatul ardi fa asbaha hasheeman tazroo hur riyaah; wa kaanal laahu 'alaa kulli shai'im muqtadiraa
"And present to them the example of the life of this world, [its being] like rain which We send down from the sky, and the vegetation of the earth mingles with it and [then] it becomes dry remnants, scattered by the winds. And Allah is ever, over all things, Perfect in Ability." — (Qur'an 18:45)
Kazzaboo bi Aayaatinaa kullihaa fa akhaznaahum akhza azeezim muqtadir
"They denied Our signs, all of them, so We seized them with a seizure of one Exalted in Might and Perfect in Ability." — (Qur'an 54:42)
The weight of the world is on the shoulders of the one who believes everything is his doing. Any failure or success is believed by him to be attributed to him. This is a very unhealthy attitude and can be the root cause of many personal troubles, from extreme egotism to self-hatred and anxiety. There is still personal accountability and responsibility, no doubt. We quote the famous hadith which was mentioned previously; Anas bin Malik narrated that a man said: "O Messenger of Allah! Shall I tie it and rely (upon Allah), or leave it loose and rely (upon Allah)?" He said: "Tie it and rely (upon Allah)." 
Do what is required and leave the rest up to Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ. If what you wished to achieve comes true, alhamdulillah, Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ has given you the power and allowed it to be. But if things don't go the way you imagined, say alhamdulillah for Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ knows best. "For We do determine (according to need); for We are the best to determine (things)" (Qur'an 77:23). Submit to Allah's will, become in love with it, and embrace it. This is the route for the one who wants to receive His love, blessings, and power.
It's important not to indulge in unnecessary self-criticism. There is a healthy form of guilt and an unhealthy form. A normal person may feel shame or embarrassed in failing an exam, but to what degree depends entirely on the circumstance. With the analogy of the camel, the question would be, do you sincerely believe you had done your part in preparation? Did you study, seek the help of teachers, assistants, tutors, or online videos? Did you do all that you could've done? If not, let this failure serve as feedback that leads to behavior change. Don't repeat the mistake of the past. If you are stressed, there's often an underlying cause; take the first step to address it because negligence would be from yourself.
In the story of Prophet Musa (as), when he tried to break up the fight, he had no intention of killing the man. As soon as he realizes that the man has died, he says, "This is from the work of Satan. Indeed, he is a manifest, misleading enemy." He felt remorseful immediately and began praying to Allah, Rabbi innee zalamtu nafsee faghfir lee meaning, "My Lord, indeed I have wronged myself, so forgive me." In the same ayah, we are told Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ responded to this call, "and He forgave him. Indeed, He is the Forgiving, the Merciful." (Qur'an 28:18).
From what we know of the story is Musa (as) did not dwell on this failure or mistake. He made sincere repentance, and the story continues. He forgave himself just as Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ had forgiven him. The only way to get rid of the skeletons in your closet is to pile so much good on top of it that it becomes hidden from view. Musa (as) shifted his focus from his dire state to seeking good that could be done in the name of Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ, Rabbi innee limaaa anzalta ilaiya min khairin faqeer, "My Lord, indeed I am, for whatever good You would send down to me, in need." ( Qur'an 28:24)
Now, if you can confidently say there is nothing more you could've done, then Allah سُبْحَٰنَهُۥ وَتَعَٰلَىٰ knows best, and we can only connect the dots looking back. But what sense does it make to feel terrible about something you cannot control?
 Hasan (Darussalam) Jami` at-Tirmidhi 2517