I suggest, you should sit down and breathe...
Just try to get the situations/people away from you who cause you so much pain and trouble. Sometimes, being selfish is the right way. Also you are a human and you have every right to demand/receive your share of happiness and peace. So be more vocal of your needs in front of others.
And lastly, expectations lead to pain, try not to develop expectations especially from people and things not in your control, things in which you could not make much effort. It will help you relax and feel better.

All the best!