@Sunseeker
Hello and welcome.
I believe that I can speak for everyone here that your frustration is shared among all of us.
I am now in year 3 of my own diagnosis, and I still feel frustrated that perhaps my doctors and I have not done enough testing to at least cure some of my symptoms. In fact, 3 months ago I told my doctor that I wanted to have her order a battery of x-rays, take a close look at them and see what, if anything, we could fix. Unfortunately, I have not yet been able to afford the Radiology she ordered until I get some of my other medical debt paid down.
In your case, having just received a diagnosis, you are still in the early stages of treatment and I would urge you to hang in there, but be assertive in getting answers. Be patient though.
It has never been recommended to me to change my diet, although I have experimented on my own. I am currently on a low-carb diet, and I find that makes me feel the best. I don't think it's a bad idea, but it seems to me that after 4 months your doctors should have the answers whether they be inconclusive or conclusive.
I don't believe hives is considered a symptom of fibro and you do not mention what other problems you are having other than fatigue, which certainly can be a symptom of fibro.
Don't feel guilty. That's not going to help anything. That will only increase your stress and you definitely do not want that.
I sometimes wake up too early and cannot get back to sleep due to pain. Those are the only days that I nap, and when I do I limit my naps to 30 to 40 minutes. Anything longer than that is going to affect my nighttime sleep. Best to maintain a regular sleep schedule. I would recommend to you activity as opposed to a 3-hour nap, but it sounds like you're so fatigued that you do not have the energy to even force yourself to engage in some form of activity that you enjoy.
Sorry not much help other than offering my support. With the symptoms that you mention, I would recommend seeing a pulmonologist for a sleep study, a neurologist and patch testing which may identify the cause of the hives. Hives are most often treated with antihistamines. Often, unfortunately, the cause is never identified. Usually, it is an allergic reaction to food, medication, physical agents or environment. But it could also be autoimmune.
Wishing you the best of luck and my support.