Could I be pregnant? Help please!?

My boyfriend and I had sex a week ago, he pulled out when he was about to *** and I've been on birth control for three years. I started my "period" three days ago, but it was lighter than normal but I had cramps like I usually do and I was moody. We also had sex two weeks ago, but he didn't *** at all then. Is this period an actual period or could it be implantation? I took a pregnancy test yesterday and today and they were both negative, but was it too early to test? I have this weird feeling in my stomach around my belly button, but that isn't where your ovaries are. Could I be pregnant?