Feeling Depressed. A pressure cooker.

I am feeling lost and depressed of late. I am not motivated at all. Most of the time I stay alone. I am feeling it very difficult to cope with people around me. I just want to count on one person. Things are getting really difficult for me both at work and in my relationship with everyone. I feel suicidal too. I am scared that I will lose the person I love. I overthink. My parents were divorced when I was 8 years old. Somewhere down the line that had an impact on me, i feel. I always look for someone who can fill that void up of my dad. I seek someone who will always be there. And when that doesn't happen I feel betrayed and devastated. I have already had many failed relationships and am coping with one about to end relation. At work I feel worthless. The girl in my team is bottomline selfish and always want to push me down and climb the stair. My manager too is biased in such matter. She always gets preference inspite of me doing all hard work.I feel i am inside a pressure cooker.