I am 15 I just recently had unprotected sex for the first time with my boyfriend we used the pull out method, I hadn't been using birth control, but I took two pills after we did it, I took them for about a week and then stopped because my period was coming, he said he didn't *** in me , and I trust that but I'm really worried because I am having brown blood And blood clots coming out.

The pull out method is a method for getting pregnant

Taking two pills after having sex , then taking them for a week will do nothing to prevent pregnancy. Birth control pills only work if you use them 100% of the time. You shouldn't trust him when he says he didn't *** inside of you. Many boys, especially young inexperienced ones don't know how to time things properly... not to mention the possibility that pre-ejaculate can occur without his knowledge. It only takes one sperm, you know.
Brown blood with clots is possibly your period coming. Since you took a few pills, it might have been enough to throw your cycle off. Brown blood is typically considered "old blood" either left over from a previous period or from trauma, such as having sex.