Anyone else's cycle become irregular once they started TTC?

Samantha
I was always regular and now all of a sudden the month we decided to start trying my period decides to be late. 5 months of me being 5-15 days late and no bfp in sight I'm wondering if I'm just too stressed and that's why this is happening? I don't feel stressed per say but I am constantly thinking about getting pregnant. I went to the doctor and she prescribed progesterone to regulate my period again but I'm still late! I would really appreciate any insight or encouragement.