Conflicted

I am bisexual and always knew I was bi. I’ve had crushes on women but have not been in a relationship with one because they didn’t feel the same and saw me as a friend so I only really have dated men. Some time in college I met this girl who I was falling for HARD, but she was in a relationship and around the same time I was also going through some personal things that I ended up isolating myself and just being very closed off with everyone. I also was not seeing her as much since she played sports , lived on campus ( I was a commuter) and was taking different classes than me. We graduated but recently I saw her again at my work and I felt everything that I once felt for her rush over me , we talked for a bit but had to go back to work. Now , I’m recently engaged , and I am feeling very conflicted on why I am having such strong emotions towards her when I saw her that day and I have not stopped thinking about her. Am I reminiscing of what I should have done back then ? Am I just reliving the feelings I had for her back then and wondering what could have been? Why can’t I stop thinking about her right now ? As much as I try to find an explanation for my feelings , I can’t and all I want is to see her again. I know no one will know the answer except for me ( hopefully soon ) but I just need advice and opinions.