Is it time to forget and move on...

There was this girl I worked with, we got along great, we talked about perosnal matters and other things but we never really got together outside of work. I had that absolute love feeling, the butterflies, nervous jitters around her. I felt that if I could stay friends withher long enough that down the road there could be more. Unfotruntatly for me she had a boyfriend. About 2 years later we still got along good but I did not really work with her just in the same building, but she was pregnant(not mine) and she never told me, a co-worker told me but she always tried to not talk about it when I was around. So I though that she did not want to speak with me anymore so I began to avoid her and just let her be which I did for good intentions, not knowing this made me look like an a$$. So she went on maternity leave and than came back to work for a couple weeks, she never showed me any pictures or said anything about it. She quit for another job a few weeks later and I have not seen her since, almost 5 months ago. I can not stop thinking about her all this time, I understand if she hates me and will never talk to me again. I feel I did not do anyything that bad to her but I just want her to be happy, and I know everyone says that but it is true, I would reather her be happy with me but happy none the less. So all in all I cant seem to froget and move on. Should I try to appologize or jsut move on with life?