I'm assuming you don't have silver fillings. Is that correct?
I've been chelating for a few years, including the use of the Cutler Protocol. I can tell you that, all-in-all, I'm feeling much better.
Chelating will make you feel worse before it makes you feel better, and everybody reacts differently to each chelator. I wouldn't necessarily worry if you are feeling worse after using DMSA. It depends on how much worse you feel. You could try a different chelator if your reaction is too bad.
It took me 6 months of chelating before I obviously felt better. I generally took only a chelator plus a multivitamin.
A trip to a sauna and drinking a lot of water may help you feel better if you haven't tried them.