Uncertainty

Hi,
First I'd like to tell you how amazed I am to see a 14y/o like you looking for self improvement. A lot of young men your age do not even take the time to consider. But you do! And this is awesome! I admire you for this!
Concerning your uncertainty and guilt after doing something "awesome" I would say this might be coming from 2 main causes.
1. The feeling of "you can't go any further than this" does not come from you. It might be someone negative in your life that made you feel that way. And now it became your own thoughts.
2. Maybe you put some pressure on yourself about what other people will think of you. So you'd start to think "i hope i didn't do it".

In both cases the problems are related to people. My advice would be :
DO NOT CARE ABOUT WHAT COMMON PEOPLE THINK OF YOU. This is also the reason we come to cheat sometimes: because maybe we care too much about what other people think of us so we hide our failures by cheating for small wins.

People will judge people anyway: when you win or when you lose.
What's important is :
Did you do something good or not?
Did you get better or not?
If you did something "awesome" 1 time.
It means you have the power to do it 2 times.
3 times. 4 times. 5 times. And to do even better.
Nothing in life is random.

The world might be shitty like you say.
But when you see how strong you are, you will start to see that this world is even more beautiful.

Again, I do not know you. But I admire you for your will power to improve yourself at such a young age and for such intelligent questions that you have.
YOU ARE AWESOME. YOU ARE STRONG.
KNOW IT.
BELIEVE IT.
SAY IT.
LIVE IT.