Kinda long but so confused please give your thoughts !!

So I got 2 BFP on dec 22nd same day AF was suppose to come and started bleeding quite a bit the 26 took another test with bloody urine got a negative ! went to the dr 28th got a BFP and the bleeding stopped they took blood and get told to come back in a week so yesterday I tested and got a negative!!! How is that even possible ??? All I can think is either I miscarried or I had my period and I'm like 2 weeks pregnant the sac measured under 4 weeks I have no idea what to think how do you get 2 positives a negative then a positive and another negative ?!?!?