First of all thank you for opening up with others and letting us know what you are going through.
I won't be giving you any advice as there is no generic guidelines or manual for every one of us. We have to find that for ourselves.
Now you are just 17 years old so don't keep very high expectations from yourself.Even the ones who are in there 60s will make mistakes and be sloppy at times.
There are few things that you must understand about yourself first and try analyzing and observing it for yourself.