I may think about all those things but then my thoughts come back to REALITY. What did I do to screw things up & what do I have to change to make it work?

Obviously there was something seriously wrong with the relationship for her to leave you when she was pregnant with your baby. So what are you going to do to correct the wrong that was done so that it doesn't happen again in the future. You can't change the past, but you sure can make changes to change the future. If she doesn't see any changes, they she's NOT going to want to come back to the same thing she left.

Stop with the romantic garbly gook & come back to reality & dealing with the issues. Wishful thinking gets one nowhere.....hard work & change is the only thing that can possibly help if help is possible anyway, depending on what it is that you did to make her leave in the first place.