How to escape a psychological pattern?

I have realized that I have been repeating the same psychological pattern for the past 10 years, maybe longer. How do I break this cycle?

I find myself at a pinnacle of joy and happiness, I am surrounded by friends and family. I feel safe, secure, and happy. I look forward to the fun to come. As soon as I reach this point I immediately crash into extreme depression. I can't look at friends in the face without being overwhelmed with an urge to cry, and extreme suicidal/depressive thoughts including self-inflicted injuries. I want to hurt myself, and loved ones. So I seclude myself from every one until I can reach a state of calm. If this means quitting my job and hiding in my apartment then that's what it takes.

I push everything and every one away from me. I become extremely secluded and anti-social. I start avoiding the friends I used to look forward to hanging out with. I put all of my emotions on shut down and become emotionless again. This part takes about 2 years.

Then I become lonely, I wonder why I am so lonely, what did I do with my friends, and I feel sad, depressed, sorry for myself. But usually by then my friends have forgotten me, or they barely say hello when I do track them down. So I clean myself up, I get a new job, new neighborhood, new apartment and I start all over again but umm, today I realized I was nearing the pinacle of happiness part, and I don't want to lose another set of friends again.

So if you can help me, please do so.