Need Insight please-1st time

Good morning everyone. I’m at a loss this morning. I got a first BFP 3/20 and another at 3/21 and 3/23 (positive-first response). A Positive on a clear blue digital last Saturday. Took a blood test from my doc last Friday and it was positive as well. Randomly took two more clear blue digital-one last night and this morning with “not pregnant” results. I am not sure what happened. I haven’t bled from 3/20 to now. Mild intermittent cramping on 3/20 and 3/27. Nauseous at 3/25 once. Really bad heart burn earlier this week, mild now. Any incite would be greatly appreciated.