up to now I have been bleeding light pink blood...

I had unprotected sex about 6 or 7 weeks ago.Two days later I had heavy bleeding for 3 days.I assumed it was my period.My period comes on the last week of every month and while it is in i dont have cramps or anything.February it came on a week early and it didn't come on wheb it was suppose to.The week it was suppose to come on it didnt.About two to three weeks later I noticed I was having headaches,backaches,lower abdominal pain,feel nauseated in the morning,and feeling dizzy.So last month my period came on when it was suppose to which is the last week.The first day the blood started out dark brown.When I put on a pad there was nothing there.The first two days I was bleeding dark brown blood.It was as if it was almost black.The third day and up to now I have been bleeding light pink blood.It as if its almost watery.All of the symptoms I described earlier I still have them.The flow is so light to the point where I have to use one to two pads a day.I recently went to the doctor and come