Constipated then diarrhea plus headaches...?

I had a horribly dark stomach ache across the weekend, the sort you associate with the start of trapped wind but didn't turn into trapped wind. I managed to pass a stool on Saturday but that was the last time until this morning when the flood gates opened. It wasn't super sloppy diarrhea but it was definitely loose. This made me feel MUCH better for approximately an hour. Then the horrible dark feeling came back. I also have a bizarre collection of other symptoms including sore neck, throbbing headache and slightly sore throat. Any clues?