gurlie... I'm so sorry to hear that.. you don't deserve ANY OF IT. I get suffering a loss is hard, i used to have 4 guinea pigs and when one of them died, I was depressed for MONTHS. I know this hurts wayyyy more than a pet, but one thing I learnt is that, those who are gone, are spiritually with you. A part of them, will stay with you. You did enough. You made him happy. You may have not spent as much time with him as you wanted, but those little moments, that little time you spent with eachother, was enough. And about your sister and mom... If they don't respect you, dont force them to. let them disrespect you, but as soon as you have your own life and can move in your own house, ignore them. If they treated you like sh!t, you shouldn't be wasting a SECOND of your time on them. just know, that I LOVE your style, I SUPPORT you being bi, your NOT an "ungrateful brat", and there is definitely NOTHING wrong with you having different interests and opinions. If they don't support that, then they aren't the right people.
My pms are always open if u ever want to talk about ANYTHING, stay strong!! <3