Hey Kiamau,
You're definitely not being stupid, and I understand what you're feeling so, so well. Life has done a fantastic job of kicking the crap out of me, and from what I've read, it's kicked you twice as hard. It's natural to be suspicious and confused when things are going right, after you've been through so much.
I won't second what's being said about positive thinking (it has its value, but to be honest, positive thinking and especially positive quotes make me terribly angry). I unfortunately subscribe more to the thoughts of one of my favourite Star Trek characters: " I always hope for the best. Experience, unfortunately, has taught me to expect the worst."
That isn't to say you should expect everything to go to hell in a handbasket, but that instead of positive thinking I recommend positive action. Look closely at the sort of stuff going through your mind right now. Is what you fear likely to happen? If not, acknowledge it for an irrational fear and set it aside. If it is likely, or has happened before, put steps in place to stop it from happening, and/or to prepare for the way out if it does. My sister is forever telling me if I just think positive and stop focusing on the negative, I won't draw negative things to me, and I can tell you that thinking through and preparing for what could go wrong (realistically, not unlikely scenarios) has worked a whole lot better for me and given me a lot more peace of mind during the good times.
For that matter, fear of success is in itself a thing. It's pretty unexplored territory for me, and I've got no idea what to do with it if I have it. What comes next? Will I turn to hedonism and fall, like Rome? Or will I be lost in all the boring tranquility, with no goals? Again, I suggest examining your thoughts, and what it really is you're afraid of. If you come into money, you can choose to remain caring and not greedy. If you are bored with or confused by peace, you can find new goals (fun ones though, instead of stuff like "stop being sad").
You seem such a good guy Kiamau, you deserve to enjoy it when things go well. I hope all the advice here helps you do so.
Blue.
