Hi, my period started on Saturday November 2nd, and my period's usually last for about 5 days; I am now on the 8th day. After the 5th day, it was very very light and would only be on a pad about twice in one day. 

Yesterday, I noticed a light brown discharge in my underwear that did not smell any different from my regular vaginal discharge. It is very watery today and, when I put a tampon in and take it out again, there is a bit of blood and the watery discharge on it. Now, I've researched and a lot has told me that it's just old blood being released from my body, but this has never happened to me before. I had sex a few days ago, because I thought my period was done. I hurt a bit afterward, but I think it was because I was not properly lubricated.

I am on diane 35 and I was recently checked for STD's and all of them came back negative. 

Anybody else have these problems?