Wow you’re really going through it!
Certainly the feeling worse is indicative of the fact that you’re on the right track as you can now be fairly certain that candida is a problem for you. If you went on the diet for a while and nothing happened you could probably count it out, so be happy in that you can be certain of at least something.
When you are in these early stages your body will be taking an absolute battering. I’m at 4 months now, and though my energy is slowly coming back I still can’t do too much otherwise I will be laid up in bed. I’m still off work sick, for instance. As your body takes a battering, all the energy you had that was holding you together before is now being diverted elsewhere. Moreover, this creates a lot of physical and psychological stress. I don’t know what this muscular band is, however I do know that the entire nervous system is acutely affected by stress, and any increase in tension will certainly multiply any muscular tension that existed already.
Are you getting proper support going through this from your relevant healthcare practitioners? Do you have a suitably experienced naturopath? Is your doctor looking after you? I think in your situation it is really important that an experienced eye watches over you.
Can you get access to acupuncture? I have found acupuncture to be really good at helping the body detox. Moreover it is a really good stress reliever!
Have you tried taking epsom salt baths? I found these to be good. However you have to be careful as often I would find that if the water were too hot I would feel much worse.
Keep looking after yourself!