Of course it wasn’t horrible to tell your bf that you didn’t want to hear about his gambling – if you were afraid then you probably had reason to be.
I don’t know whether or not your bf is addicted to gambling – but I do believe that you should not be afraid of the person you love. He promised he would stop gambling and he reneged on that promise, he gambled until 9 or 12 am and was taking sleeping pills, all of which implies he is not in control of himself – this is not behaviour to feel proud about. How old is he?
You are right that the brain is powerful so instead of allowing yourself to look down, use it to look up and see the good things in your life. You are obviously a very caring person; you are unique and special so allow yourself to feel those things. If your bf is addicted, his addiction would take you down with it – that is reason enough for you to be proud of yourself and the way you behaved.