Can someone tell me if this is possible??? (Read entire post please)

Is it possible to be pregnant again If I miscarried on May 9th and bled for a few days?

I tested the day I stopped bleeding and on the following day(May 13th and 14th) and my pregnancy tests were negative (stark white). I don’t see my doctor again for another 2 weeks for follow up blood work. Well today I tested and I for sure got a positive (all pregnancy tests were from the same box)