Regarding feeling like you are dying. I have been there before. You might want to check with your doctor and make sure he/she knows how absolutely miserable you are. But say it with detail, such as I need to do such but I have had to lie on the couch all day.
Regarding the itchy lumps, you might want to do a search on the word pretibial. There is a dermatological condition that occurs in some Grave’s patients usually on the legs. May or may not be that but maybe you could get an idea from reading what others have said.