Bleeding after sex

I'm 4 weeks pregnant. (Got a Positive starting at 10dpo and it's been increasing since) everytime my husband and I have sex , I bleed ALOT. Like it looks like a period. I bleed for a few minutes after we finish and then I completely stop bleeding without even spotting after we're done.

Has anyone else had this? What was the outcome ? I'm gonna call my dr on Monday but I'm just trying to figure out what it could be before then. TIA