The most obvious thought that comes to mind could be that you are constipated. Does your bowels move regularly?
If not, because of the nausea and shakes, I would suggest a neurologist ... could be a lot of possiblities here ... some of them not so good ... so don't ignore it.
Thanks, i took some excedrin today when the headache first started up & it felt like it just got worse after it. Do you get all those things with it when you have migraines?
those don't sound like headaches, they sound like migraines. Most migraines last about an hour, but can last for a few days. There are tricks to not get migraines, and there are some unavoidable things that cause it. A lot of women get menstrual migraines, and some just can get them from stress, from caffeine, and even chocolate can be an inducer. An easy over the counter medicine that can help is Excedrin Migraine, or you can see a doctor and they'll give you some good medicine and put you on a watch list. If migraines become constant you'll have to be officially "diagnosed" with migraines, but to be honest if you've ever had a migraine you know the difference between it and a headache.