Hi Tania.

It sounds like you're in a pretty tough situation right now.
I don't really know what to tell you, but I've had my fair share of difficult relationships, and I go to a school in a different country so I know what it's like to miss your parents too. Neither of those is much fun, but with depression they're downright unbearable. Do you currently have a therapist or maybe a school counsellor you could talk to? My counsellor was really helpful, especially because I didn't think my parents would understand how I was feeling. She helped me figure out some of my problems and take steps to fix them. Now, I'm slowly starting to piece my life back together. It sounds like your relationships with your ex and your parents are complicated, and it might help to get an objective, professional opinion on things.
Please take care, and in the meantime keep posting.