In November, my period came on the 15th and lasted around 5-6 days. I had protected sex with my boyfriend on December 9th, but the condom didn't break and he pulled out as well. My period was a couple days late, it came on the 18th this month and ended on the 24th, except it usually ends in a brownish color but this time it was a very light pink at the end. Since my period ended, I've been having these twinges of pain that last for less than a second and occur every 20-30 seconds or so in my lower abdomen, everywhere from just above my pubic area to just below my belly button. I researched that and it took me to a bunch of pregnancy forums which made me really paranoid that it could be implantation cramping. However, this has been going on for like a week and it said implantation cramps last for around 1-3 days. Within the last week I've taken 2 negative pregnancy tests and I plan to take the third about a month from when we had sex. Even though I got my period is there a chance I could still be pregnant? I'm getting a lot of mixed results and I just need some peace of mind. And if I'm not pregnant, what the heck are these spasms of pain in my abdomen??