I've been having very bad headaches the feeling of the headaches are popping pounding and also stabing pain for 3 weeks now i also been dizzy its worse when lay my head back setup and standing up straight i also had diarrhea what could this be?

This could be...: Could be time to see one's doctor. Most people get a headache at some time, such as from colds, infections, lack of sleep, too much driving, long hours on a computer, stress at work, etc... An increasing or bad headache, recurrent headache (as in this case), weird headache, or with other worrisome symptoms should be evaluated. A person can write down details (a timeline) to show her doctor.