I guess I'll put this here lol

Idk where to post this but since I'm 26 weeks pregnant and I think that might be the problem I'll post here.

So you might have seen one of my earlier posts saying I got an overnight job and I was nervous about telling them and so on. Well, I went for my interview on a Saturday afternoon. It went well and he said I was hired. We talked about hours I want and if I was able to do a few day shifts for orientation and training and I said yes. He had me fill out papers for a background check and told me he will call me as soon as he gets the results, and said that would be by wednesday, Thursday at the latest and we'd set up a time for me to come in and fill out the w4 and other papers. Well I waited. It became Wednesday and then thursday. Friday I called him and he wasn't in, he had the day off. They said he'd be in in the morning from 6-3 and they'd give him the msg to call me. Well he didnt. This wasn't this week. It was last week. yes I'm still dwelling lol. Has this happened to anyone? There would be nothing that came up on the background check. I thought of two things that could have happened. Either he called my old job that I got fired from or he somehow found out I was pregnant. But here's my question, why would he bring me into an interview, hire me and THEN call my old employer? Lol doesn't that seem backwards? Do employers do that? What do you think happened?