What Does Bleeding Between Periods After Having Unprotected Sex Mean?

Ok, here's my issue. My husband and I had sex on Oct. 3rd, and the condom broke. 4 days later, I had my period, right on time as usual. It was completely normal- heavy flow, cramps, 6 days. Now, on Oct. 25, I started bleeding, and it has lasted four 3 days now. I've been having a period since I was 11 (now 32) and it has never come early, at least not this early. Also, it's a super light- like barely there- bleeding, no cramps or pain of any sort, or any of my other period symptoms, and quite a bit too early for my period. So, what I'm wondering is, could I be pregnant? Could this be implantation bleeding? Or is it something else altogether?