Positive Pregnancy Test but Not Pregnant

The last few months I’ve been getting positive and negative pregnancy tests. First time I passed it off as a chemical pregnancy. Then the next month another positive test and negative test I called my doctor. After another pregnancy test along with ultrasound we see I’m not pregnant. This is the third month I’ve gotten a positive and negative pregnancy test. Has anyone see anything like this? I’m a mother of three so I’ve seen a lot but nothing like this. Should add that the first two months I was on the pill and the last month we which to condoms because we thought the pill wasn’t work since I was getting a positive test. My Ob appointment isn’t till next month to get my IUD so I called my regular doctor who will see me Monday morning but the wait is killing me. I’m spiraling looking online. If you made it this far thank you 🥺😭