Need help. Bad.

I am 37 weeks preggo, only posting this anon cause hubby comes on here sometimes ha. Anyways, I don't know if it's because I'm pregnant or what but my husband has been married before and we met right when it was ending, papers already done and whatever BUT I still was put into that mess. That was a over a year ago..but lately for some reason I CANT stop thinking about it. I obsess over it. I go on Instagram and look at shit that doesn't matter and then get upset. Please tell me what I can do? I know it doesn't matter, they were literally only together for like a year too he says it was the biggest mistake ever and I believe him. I just really need advice . Thanks girls.