Since Friday, I've been having light bleeding that's brown in color. The first two days were enough to make a sizable stain on my pad, although it has tapered off. This is when I'm supposed to be having my period. I'm also experiencing slight cramps and back pain, which are my usual symptoms, although not nearly as intense as they are normally. I have no nausea, no change in appetite, no sudden fatigue, or any other typical pregnancy symptom.

I've recently become sexually active (protected, of course) and I'm worried that this could be implantation bleeding, despite how unlikely it is. My cycle is about thirty days and it appears I'm much too far from my ovulation for this to be implantation bleeding, since it's been more than 12 days since my ovulation. However, I have no idea what else it could be.

Has anyone experienced an extremely light period after becoming sexually active? I've never had such a light one before and it's worrying me.