What you are experiencing is very normal. Random memories about past events, especially traumatic events, is common. What I suspect is happening is that you are beginning to work through the deep emotions you experienced in the past because you are beginning to feel safe enough to do so. And you are working hard to confront the emotions you have from your experiences and that is going to trigger other thoughts and memories from your experience.
I can only imagine how hard it would be to pick up and move suddenly because you are not safe where you are. Going somewhere where you have never been before, sending your daughter to an unfamiliar school and trying to manage on savings only. That would be unnerving at best. And since you are thinking about this constantly, it most likely means that you felt very strongly about it at the time but have never had a chance to work it out. You just dealt with it then moved on to the next issue. Now you feel safe enough to begin to cope with everything you went through.
This is a good thing to bring up with your therapist and work out. I think there are a lot of feelings behind these memories that are trying to get your attention through pushing it to your consciousness. With her help, you can explore how you felt at the time and allow yourself, finally, a chance to cope with what you experienced.