One of the most common symptoms of depression is becoming much more "numb" to your emotions. I consider it more of an "auto" mode. But yes, I can understand that your mind is going through so much stress that it's shut down some of your emotions to help and listening to other people's problems can be super triggering and you're dealing with your own problems and so it's taking up all your energy. Which makes it really hard to listen to other people problems. Please don't get down about this. For a long time I couldn't process anyone else and didn't feel like listening to anyone either. No one can be nurturing all the time without destroying themselves slowly.
Your family's choices will always affect you when you're younger. But the most important part is that you're trying. You're working on it so give yourself time to grow

But yes, I sometimes find it hard to differentiate my choices from my parents but that's because we're still young.
It's a really sad feeling to think you don't belong

I get it a lot too. Especially here at college. I don't really know where I belong and the people I hang out with currently, I know that the friendships I have with them won't last and that it's all circumstantial. I feel distant from them but for me it's extremely important that I have friends otherwise I spiral back down into really deep depression so I try my best to be friendly. But it's really difficult. I suppose the most important part is that this world has so many types of people that you'll definitely find people you can be close to. And also, the most important part is that you are comfortable and happy. Don't worry about underachieving because if you're happy you'll do your best. Especially with being lonely, don't view yourself as selfish when it comes to making friends. I'm sure you were very important to them and they appreciated the friendship.
And please, I promise we'd probably get along really well in real life

But I'm glad you feel like yourself online