I don't know what the heck is going on, so I'll just explain...
I am 26 and have been in the same monogamous relationship with my husband for the past 9 years. I have a Mirena IUD (four years) and nothing has changed by way of sexual habits in order for this to be occurring. My period ended about a week ago and we had intercourse two days later which resulted in slight bleeding. Three days later (today), we have sex again and the blood is really bad... almost as though I started my period (which I obviously did not). Beyond this, I had a short period this month (4 days) and prior to that I began developing some serious PMS problems (which are very unusual for me) for an entire two weeks before my period. My abdomen was very bloated and my breasts were very sore... I was starting to worry that I was pregnant. The weird PMS has happened twice in a row now - the bleeding is a new problem.
I just wanted to know what on earth could be happening...