So, 2 weeks ago I had my period. I had sex shortly after it ended, then got a yeast infection. During the treatment of the infection I started bleeding--it felt and looked like my period, but I just had it a few days prior. I went to the doctor for the treatment and they ran a STI test, all of which came back negative. I just had sex a couple hours ago and it hurt right from the beginning, but I thought I was fine so we kept going, then he noticed that I was bleeding. A LOT. I'm on the pill. As an 18 year old girl who is always regular I am extremely concerned!!