Does this sound like an ectopic pregnancy?

I found out through urine test at my Dr's office that I'm pregnant. I should be about 4-5 weeks according to last period. I mentioned that I was having some pain on my lower left side so she ordered an ultrasound. The ultrasound tech could not see a fetus or sac and said it might be early still and ordered a quantitative blood test. My hcg level was 1200. The dr told me to come back in two days for another hcg blood test. Since then I have been having more pain on my lower left side. Sharp and dull crampy pain. The pain is intermittent. The sharp pain seems to radiate along the side of my hip bone. I've recently tonight also had some diarrhea and cold sweats. Could this just be really bad round ligament pain or does it sound like a doomed pregnancy?