I saw a little blood, could it be implantation bleeding?

My boyfriend and I had protected with a Trojan condom about two weeks ago. Last night, I went to his house, and he fingered me for a long time and did it fast. He was pretty rough with me. (I apologize if you are grossed out). Anyways, after I got home from his house, I noticed pinkish-red and brown spots on my underwear. Was this implantation bleeding OR abrasion? Could I be pregnant?