severe pain and lower adnominal pain

I'm having servere pain in my lower abdominal area, and the 1st day I just had a little bit of pink blood, and now it's loads of it 4 days later and I'm in a hell of a lot of pain, my moods have changed, I'm knackered and I feel like I can't catch my breath sometimes, but that could be smoking I don't know.  However I was 8/9 days late and I took a test it said negative I don't know what else it could be?