Opinions?

My last cycle was June 26, my period lasts 4 days usually, and my cycle is around 22 days. I had sex July 6-8, I'm not on my birth control anymore, we didn't wear a condom, but he pulled out. I also drank a lot and cannot remember Saturday night, and I think I had sex with him again, but that one I do not remember, nor do I remember if he pulled out. I asked him and he said he did, but that we had sex multiple times in a row. On the 8th, I took 2 birth control pills and one 3 days after that.

I got period like cramps and spotted yesterday and did bleed onto my underwear overnight but I haven't filled a tampon yet. I'm supposed to get my period this week (tomorrow I think) but i read somewhere about implantation bleeding; and got freaked out.

I am waiting to see if it's heavier tomorrow but would like some input! Could this be early pregnancy?