I have a few regrets in my life.
Me being a 25yr old loser makes it so much worse. I can't seem to let it go.
Think about it -
If you waste your present moment in regretting for past, later you will also regret for this moment of why you wasted such precious time and young age in regretting, and you'll wish you had moved on faster and exploered better things. Your time and energy are not for regrets. You are young and have lots of potential that you will not have forever in your life, so think of utilizing that and give value to yourself. Just don't forget to learn from it, becasue learning from mistakes applying them in life is very important, regretting is not.
Whatever happened has happened, now you only have 2 outcomes of it to save in your memory -
1. Learning, that will keep you positive and motived in future life and help you make better decisions
2. Regret, that will trouble you every time you think of it, demotivate you, depress you, weaken your self-confidence.
No one would ever like to choose 2nd option, but unknowingly they do so by their habit of over-thinking. So try to change that habit if you have, and stay self-motivated.