Advice on missed period??

So I’m late by a day according to this app. This month I started heavily working out to lose weight and I read that that can affect a cycle. However, I am SO paranoid that I’m pregnant. I’ve never had sex and all my bf and I have ever done is oral, and I read that it’s pretty impossible to get pregnant that way. Even planned parenthood says that it’s impossible on their website. I’m probably just being over cautious but I’m so anxious about it. Someone tell me I’m just crazy?