Bleh I’m slightly panicking

Sooo I had my baby 2 months ago and usually with my other babies I start my period 6 weeks PP. I don’t breastfeed. Last week Thursday- Saturday I had very light spotting only there when I wiped. There was also cramping. It stopped and no period followed. Fast forward to yesterday I had sex with my husband (and yes it’s been unprotected) and I started bleeding a little bit and then it stopped. Nothing heavy. I thought for sure it was my period but nope. I took like 4 pregnancy tests last week and they were all super negative. I don’t know what to think at this point. Okay just needed to vent. Please don’t rag on me. Thanks !