What Causes Vaginal Bleeding During Intercourse Along With Sore Breasts?

I have always had normal, regular cycles. However, this previous month I experienced BV like symptoms. Discharge was clear, watery and didn t smell good. I used peroxide several times a day and it would seem to get better, except every time I had intercourse it seemed to come back(long term relationship). On day 14 of my cycle, during intercourse I had a rush of blood, maybe a tablespoon or two. Then no blood. The next day I spotted. The next day after intercourse I had more blood and spotting. My breasts feel sore, my lower abdominal is very tender and it seems like the left side of my lower abdominal is more sore. I have never had mid cycle bleeding before. I have had two pregnancies before and never had a period while pregnant. What could this be?