What Is Implantation Bleeding?

What kind of bleeding is this? Implantation or light period? Please answer!?

• I'm 23 years old. Okay, so the last time my boyfriend and I had protected sex on June 3rd and June 4th. However, before he put the condom on he had been inside me without anything on, but it was for about a minute. He did not orgasm. Anyway, I've NEVER had regular periods. I keep track of them using an online calendar, and my last period was May 7th. My expected period was supposed to be June 19th. On June 20th, I got some strange brownish discharge, the kind that you usually get when your period ends. It's been 6 days and I only see it when I wipe. Nothing shows up on my pad but a smear. It's been almost a week like this. I've heard this could be implantation bleeding, but it would have been 17 or 18 days days since conception if I got pregnant on the 3rd or 4th. And that seems like a long while later. Also, it's been lasting on and off for almost a week, so I'm not even sure it's that because I read somewhere that implantation bleeding is only a day at most. I'm NOT trying to get pregnant so I hope it's not that. As for symptoms, I've had anything unusual. My BBT has not changed recently, with the exception of a temp of 99.0 for maybe an hour before going back to 97.6. I've been slightly fatigued and a little achy, but that usually happens when my period is coming. I've also been under a great deal of stress with college classes. My sleep schedule completely changed and so have my eating habits due to my new schedule. I also stopped working out. I've heard these are all factors that can affect my period. So could this just be a really light period? Or implantation bleeding? Is my period coming but just taking its sweet old time? I've just never had this before so I'm worried. I'm also not on birth control. I cannot be on it for medical reasons. We use condoms.

• Answer:

  I'm not sure, best thing would be to take a preg test.