Not really pregnancy related

I am pregnant, but this stuff has happened before I was pregnant. I am married, pregnant with my second child. I still think about how my ex of 3 1/2 years is doing and sometimes I get jealous of his current wife because I always expected us to be together in the end. That’s clearly not the fact. Also, I have dreamt about a guy I used to like in high school and he has admitted to liking me (WHILE IN HIGH SCHOOL) but we never dated. I feel bad, but I wish I knew what it would’ve been like if we have dated, in the past. I do but don’t enjoy these dreams because they kind of let me live a different life than I have now. I would never act on these dreams but is this normal, or does this happen to anyone else?