what's wrong with me, please read ! ( mental problems)

I'm not sure if I sound like a idiot but I feel like I have a problem for always thinking about others then my self! And it effects me so much, I'm a strong person but I worry about everyone else instead for example I've finally got my own little flat and I'm so happy but I feel awful because I have such a bond with my little sisters I feel like im a bad person for moving out of home, and feel like I shouldn't go.  I got offered other jobs but I felt bad for my boss so I stayed there. I used to stay at my stepdads every weekend untill I get older now and I feel so bad and stay over as much as I can(I love it there) , that's just a few examples. can't explain the feeling but I've got this thought in my head all the time that the people close to me are going to feel bad and upset even when they might not and it eats me away inside. I feel like they would be upset, and it's over stupid things too . It's just making making decisions and big steps harder. It's like a mental thing