Ok so this happened to me.
we were trying to get pregnant, I knew when my period was due, it was late so I took a test. It was positive. I did a clear blue digital - it was also positive showing 1-2 weeks which put me at around 4-5 weeks pregnant going by my last period. All fine. 4 days later I started bleeding - light at first then it turned heavier like a normal period. I took another 3 pregnancy tests over the coming days and all still said pregnant, I was still bleeding. I phoned the midwife (who I hadn’t even seen yet for the inital booking in appointment) and she said that it was likely to be a chemical pregnancy and that the only thing to do was wait and see if the bleeding stopped and then check another pregnancy test after a few days. She said that the hospital wouldn’t offer a scan or anything at that early stage because it’s extremely common and unlikely to be anything seriously wrong - lots of women experience chemical pregnancies and never even know, they just assume it’s a period. A few days later the bleeding had started to tail off, I did another test and it was negative. 3 months later I fell pregnant again and that pregnancy resulted in our eldest son
All you can do is give your body time and then do another test in a few days/a week. Take it from there.
all the best xx