3 periods a month??

I just want to start with I have a dr appointment scheduled tomorrow but I wanted to ask on here Incase anyone has had the same issues. I’m 1 year postpartum so I don’t think that’s my reason but I’m on my third period this month. It almost seems like every time I have sex I start a new period. It’s very painful and honestly I’m tired of bleeding. One week out of a month is plenty enough. If you’ve had the same issues what caused it and what resolved it?