Im only 5 weeks along and this day has scared the crap out of me (literally)

I had horrible poop cramps all day and have experienced diarrhea at least 5 times. During one episode I had a tiny dot of brown blood and it was followed with menstrual type cramps. I believed it to be the end for me but then it stopped about an hour later. Then my poop cramps picked back up and Im miserable. Whats going on?