I Feel My Depression Coming Back

I'm not suicidal this time, but it feels like a pain growing larger inside me. I'm not satisfied. I don't finish much, as I'm constantly starting over. I feel like my entire life has been start-restart-never finish. I feel like there are various personalities inside me. One is always unsatisfied with the actions of the previous, so I start over and do it differently. I don't know how to get out of this cycle.