Implantation Bleeding or Period?

My boyfriend and I recently decided we would like to try for a baby. We missed our chance to conceive on my ovulation date but after I calculated it up, only by a few days. We tried three days straight, multiple times. This was a little over a week ago. I missed my period by two days and got it Saturday. It was brownish/red in color and not very heavy. So I suspected it was implantation bleeding. Yesterday evening, the flow picked up and is now a dark red. I'm not sure whats happening but I get a few cramps in my uterus every now and then but other than that, I feel normal and the flow is lighter than its ever been. Someone please help! Thank you.