It sounds like you are still feeling Grief, grief over a lost childhood, grief over an unsatisfying parental relationship, grief over a late start in life.
The premier academic studying Grief was Elisabeth Kubler-Ross who proposed Five Stages of Grief. These were: Denial, Anger, Bargaining, Depression, and Acceptance.
Her original theorizing posited a linear movement through these stages until Acceptance was finally reached.
Now it is thought that we can move through the stages in different orders or even cycle from Acceptance into previous stages and back again multiple times.
Maybe you can see yourself in one or more of these stages. Sometimes it helps just to put a name to something.
All this to say that you can feel okay about it one day and then go back to feeling unsettled. And that's actually quite normal. It's a process not an endpoint.