Hating your past self after therapy

TL;DR : I've been to a therapist, read some books, and faced up to the fact that I lived about 30 years of my life in a state of high functioning depression. I felt pretty good for a while. Lately, over the past 2 years or so, I've spent more time reflecting on my past and realized how pervasive the depression was. I hate my past self for the opportunities and experiences I missed out on. Anyone else experience this?

I'm in my mid-40s and about 7 years ago in the midst of marriage counseling, realized and accepted that I'd been suffering from high functioning depression for most of my life. I was always a shy, anxious and withdrawn kid with zero self confidence. Mental illness runs in the family — between an overprotective narcissistic/BPD mother who had a traumatic childhood and depression on my father's side (an uncle who committed suicide, and a grandmother who was depressed, obviously even more so after losing my uncle), I had those possible tendencies, but add to that my parents' divorce when I was 5; a narcissistic, emotionally and verbally abusive stepfather who came in to the picture when I was 6; having to help care for 3 younger siblings; and losing 3 grandparents, an aunt, and my father between the time I was 14 and 18 — and I was not a happy person growing up. But hey, I always got good grades and stayed out of trouble, so it all looked fine on the outside.

Fast-forward to my late-30s — I was in marriage counseling. There was no passion in my marriage and we had different expectations in the marriage. I expected something close to 50/50 on chores & duties while she expected someone to take care of everything for her. Between my unrecognized depression and her acknowledged depression, we weren't a good team; we didn't support each other when we needed it most. Around that time I had a major confrontation with my parents; basically, I really stood up for myself for the first time ever and they couldn't believe it. I opened up about a lot of things, confronted my parents about past issues, and the aftermath left me emotionally exhausted and I ultimately went through what was luckily an amicable divorce.

Now, over the past few years as I've moved, met new people and dated, I feel much better. However, I feel like I've grown detached from my past self; looking back feels like looking back on the life of someone else, and I feel sorry for, and I guess hate that person. I missed out on a lot of happiness and joy. Yes, I did have some good times and I know I should be grateful because it always could have been worse, but I've just been wired to look more at the negative. Now, I've never been a nostalgic person, or one to reminisce about the past. I don't hold onto a lot of tradition. Aside from very early in our dating life, my ex-wife and I never really discussed our past. Now, having dated again and going through that period where you share your life stories, I've come to dread talking about my past because I just think of what could have been and I get depressed sometimes after thinking about my past. Maybe it's all at this age when people reminisce more, but the people I've met over the past few years seem to talk about their past more than others I've met at earlier times in my life. I wish I could just wipe all the memories.

I suppose all of this will pass, and it won't bother me so much. But this is one aspect of healing I didn't expect. Unearthing the past and looking at it anew is not comfortable; there's pain in looking at the past with new eyes.