PLEASE HELP ME

So the other day I had sex with my bf and when we were done I realized I was bleeding and was a little confused ( It’s been 125 days since I’ve had a period, I’m on nexplanon) and I only bled for that time period nothing after and nothing before. Well today I had an appointment to get checked because I had a yeast infection well when she put the thing inside my vagina (can’t remember name) and took swabs to look at discharge and we were done with that they left and I was cleaning myself off there was blood again and I thought I should put tampon in bc seemed like I was starting my period. I’ve just changed my tampon and there is NO sign of blood on it. Is it possible to only bleed when something goes into my vagina bc of yeast infection and swelling ?? I’m very confused and scared. I also got tested. Me and my bf were tested before having intercourse.