OK, first off, be warned. I'm not a doctor so what I'm going to write here is really just opinion. It is based on my own recent experience and also on the description you've given here.
It sounds to me like you have magnesium deficiency. Just do some Googling for magnesium deficiency and see if the symptoms listed sound familiar.
There are several reasons that people get magnesium deficient. One reason is that the typical American diet simply doesn't supply enough magnesium. Another reason is that caffeine prevents magnesium absorption. In my case, caffeine is probably the reason why I got so deficient (and still am, just found out about this a few days ago).
Here's what I recommend.
1) Buy JigSaw Magnesium w/SRT. It's time release. Trust me, almost any other magnesium you buy will give you diarrhea. Our bodys have trouble absorbing supplemental magnesium and if it doesn't get absorbed before it hits the big intestine it will just turn into awful watery diarrhea. The only other one magnesium supplement I've seen that gets good reviews is from "Source Naturals", their Magnesium Malate. You're probably going to need to take somewhere between 400mg and 800mg per day at first to build your system back up. Basically, you want to take as much as you can handle without getting diarrhea up to 800mg (don't go over that without the advice of a doctor or nutritionist). You'll probably need to stick with larger doses for several months but do your own research on this. Once again, do not go to your pharmacy and buy magnesium their. Basically everything on the shelf is very likely to give you diarrhea. Even one 200mg magnesium citrate tablet does it to me. My body just can't absorb it all before it gets to the large intestine. And don't buy calcium and magnesium. It won't help one bit because there is always more calcium than magnesium in those and that doesn't help you one little bit when you're magnesium deficient.
2) If you're skeptical on this or if you don't want to wait for your magnesium to arrive, you can very easily try out some magnesium to see how your body responds. Go to your local pharmacy and go look for Magnesium Citrate in a bottle in their laxative department. If your pharmacy is like most, you should find some stuff there that has 290mg of magnesium per fluid ounce. Just take about 3/4 ounce to start with and see if you don't feel a change within 15 minutes. Be very careful with this stuff or once again you'll have diarrhea. I actually sip on it and let it soak in in my mouth and throat. It gets into my blood stream faster this way and it makes it so I won't get diarrhea from it. I usually consume about one ounce in the morning and maybe 1-1/2 to 2 through out the afternoon and evening. I'm only doing this right now because I'm waiting for my JigSaw magnesium to arrive.
3) If you use caffeine, start cutting back on caffeine but don't go cold off turkey. If you go off cold turkey you might get one of the worst headaches you ever had and it will last three days. It would probably be best if you eventually quit caffeine at least until you're feeling good again. Caffeine works against magnesium absorption big time. Just Google for it and read the article at **********.com
4) If you drink at all you should probably cut out alcohol too. I don't have much to say on this because I haven't read much on it since I don't drink.
If you don't believe what I'm talking about here with the magnesium just start Googling. Your symptoms match magnesium deficiency to the T.
You might also read up on Lyme disease. Do you live in an area where Lyme disease is known to exist? Do you spend time out doors in areas where there are deer? If your problem is not a magnesium deficiency then you should be evaluated to see if you're at risk for Lyme disease.
If the magnesium doesn't help go see a doctor ASAP. I don't want to scare you but I believe there are a variety of diseases (some of them scarey, some of them not so much) that do include the kind of symptoms you're describing. But just remember, even some of the best doctors will diagnose you with a disease such as fibromyalgia or diabetes but totally miss the fact that you're magnesium deficient. There are many diseases that are confused with magnesium deficiency.