Well, having been in situations like this, sometimes I feel the ER makes you feel worse. At least in my cases, having been undiagnosed at the time, having to wait for 4 or more hours only to have nothing done. I would have rather been in misery at home.
That being said, you are the only one who knows your body. If something isn't right, go! They will at least get you on an IV to get you hydrated and possibly something for the pain (although that's always up in the air). And you may get a good Dr. who has some insight into why you aren't feeling well. But again, as I caution everyone, many ER drs won't take you seriously if you tell them you have Fibro. Someone even posted their experience on here about it.
As far as your head, do you think you may also have a migraine? I know some people can get seriously HORRIBLE migraines that make them feel like they are dying. If this is the case, the ER would have medication for this.
Please keep us updated. I really hope you feel better Tara!
Taking 2 Lialda and Canasa 1x daily.
Protonix, 50 mg Synthroid, Migraine meds when needed
Also taking Probiotics and Fish oil supplements