Pink vaginal discharge?

Hello!

Yesterday, after urinating, I wiped and noticed a bit of pink discharge on the toliet paper. My immediate thought was implantation bleeding. I have been on ortho tricyclen lo for nearly 4 years. I took a short 2 month break about 2 years back but otherwise I have been very consistent with it. I last had my period on Aug 24 and had sex with my fiance 4 times between Sept 1-Sept 5 (he lives in another state, hence the sex in one confined period of time, lol). The discharge was on Sept 9. Could it be implantation bleeding that soon?

We are not trying for a baby...our wedding is just a little over 9 months away. (that would make things interesting, wouldn't it?? lol)

Obviously, it could be a number of other things...but the thing is I have absolutely no other symptoms...no fever, no cramping, no pain...nothing. I have never had spotting (at least that I've noticed) in the 4 years I've been on the pill, so I don't that's it.

I know no one can diagnosis me over the Internet (especially if you're not a Dr.) but I was just hoping to get some feedback on what I should be looking out for (other symptoms, etc). If I don't get my period on time on Sept 21, I plan on taking a pregnancy test.