I'm super paranoid. I'm going onto THREE weeks late. I've been feeling more tired than usual. I get…

I'm super paranoid. I'm going onto THREE weeks late. I've been feeling more tired than usual. I get headaches more than usual. Appetite hasn't been the same. BUT, I've had 4 negative pregnancy tests, and my doctor upped my dosage of Sertraline. I've read that can mess with your menstrual cycle. Feedback?