Anyone know why I'm hurting?

I have a pain in my lower abdominal region. It is mostly like an extreme cramp for a quick moment that makes me grab it then it gone. It goes away as fast as it appears. It's been doing this for about a week now and I don't know why. I had a little bit of dark spot on my panties I yesterday. It wasn't a lot at all, barely on my panties but it was borderline brown. I'm nowhere near my period. Should I go to the doctor?