Should I be concerned? (possible pregnancy)

Hey, I just need a little input on whether this should worry me or not. I started my mensies on the first of the month and have been regular for the last four months or so, but before that I'd been very irregular. I figured it would be safe to have unprotected sex with my fiance during menstruation seeing as how I wouldn't be scheduled to ovulate until around two weeks after (very risky, I know. But it was a caught-up-in-the-moment thing). My period ended around the seventh and then I started spotting a little on the 16th (just some light-pinkish discharge which later turned into a dark brown. I have NEVER had any light-pink) and have been for about eight days. Now it's stopped and I should be close to starting my actual period, sometime around the first.
I don't have any pre-menstrual symptoms except sensitive (sorta tingly) nipples and some crazy mood swings and emotions. Not much cramping at all, just a little and very spaced out. I usually cramp severely around the week before I start.
And one more odd thing. I am a cilantro addict. I'll eat the stuff on pretty much anything and all of a sudden I can't stand the smell or taste of it. It literally makes me ill. Any thoughts? I'd really appreciate any comments. I'm very small-framed. I'm six foot five and I weigh eighty-five pounds and I don't know if my body could handle a pregnancy right now. I hate the thought of a miscarriage.
Thanks for all comments in advance.