I've been faint, exhausted, headaches, and cramps - going on for a couple weeks. today i got diarrhea. neg preg test. miss period but i'm irregular

Endocrine problem: From the symptoms you listed, the culprit could be a glandular problem, anything from thyroid disease to ovarian issues. You should see your doc for a full evaluation, where tests can be run and the underlying cause found and treated. If the diarrhea is persistent and/or you start vomiting, you would be at risk for dehydration, increase fluid intake and get rest. If not better, see doc ASAP.