hey man it's quite normal to fall asleep and feel really tired after you ejaculate, it's kind of like relief after the act. Don't worry EVERY GUY MASTERBATES but nobody will ever admit it, so don't go talking about it)) Once you started doing it you can't stop, you will always want to do it, you can only replace masterbating with a girl. Don't worry everything that you wrote was normal, its okay to do it just don't do it too much because it can become an addiction.
Guys usually won't admit that they do have problems with masturbating. My bf never wanted to tell me that he is addicted to this. I started to notice this when he started to refuse me totally. No connection, no intercourse...nothing :/
So when I decided to leave him, he admitted me that he has this problem and that he wants to quit masturbating.
The first step was - visiting psychologist. He talked to him about this issue (it was hard for him, but he did it).
He told him that he needs to find some things that will make him focus on them. My bf started to read books and he never did that before. Boys just need to focus, that is all.