From bochur to bochur
I know how you feel, I feel your pain, I have felt this way for years. I congratulate you for finding this out by your self. I needed the help of others.
I can only share my experience: For me the main reason of falling - is because i feel that pressure "to finish shass" "to be the biggest masmid" "to be a talmid chacham" - TODAY!! Now!! So not being able to fulfill those expectation will create lots of "i failed" messages. Then I escape to a much sweeter place, a alternate reality. Not only by ma*****tion but also by fantasizing alternate realities.
Recognizing the problem is a huge step towards recovery.
Further steps could involve: Realizing that you are NOT lazy!! Who knows Shass?? Is that realistic?? Hey, Your working on it!! And/Or realizing: Yes! I am lazy, so what!? Thats how Hashem build me - BUT Im working on it - and that all that matters. After 120, Hashem wont ask us do you know shass - Hashem will ask us "did you give it all you got?"
Don't think back - its no use, think what can I do NOW.. and as inna said, its no quick fix - its
a new way of living. Its work - but you will love it(=yourself)