Irregular periods

Hi ladies . So my periods have been so crazy lately. In the month of February and March I had 2 periods a month. April I didn’t have a period at all. My boyfriend and I had unprotected sex the beginning of the April and he finished in me. A couple of weeks after having unprotected sex I was cramping as if I was going to start my period. My face broke out and I was getting hot flashes. When I was in the restroom I wiped myself and there was very light pink blood. So I told my self my period has finally came, but it stopped after two days. I took pregnancy test which all came out negative. Here we are with no period either. Can anyone tell me why I’m experiencing this? :(