I Lost My Virginity To My Bf On Nov 1.

I lost my virginity to my bf on nov 1. He used a condom with spermicide in it and he pulled out before he came. He tested it afterwards and there were no holes in the condom. My period was due yesterday but didn't come. This morning I used the bathroom and I had a brown discharge with a single string of red blood much less than I would normally have for a period. Is this implantation bleeding? In so scared, we did everything we possibly could to prevent pregnancy.