I Have Degenerative Arthritis Which I Have Had For 20

I have degenerative arthritis which I have had for 20 plus years. I am currently dealing with several new symptoms and no one seems to be able to solve what is going on. Last year I started to have some swelling in my ankles, so my doctor gave me Lasix which did help some. Also I have unexplained itching which sometimes keeps me awake at night, there is no rash, bumps, or irritation. I use the same lotion as I have always used and have had not added anything new. I was also told that my most recent blood work came back with low CO2 levels. I am not sure if I should be concerned with this or what my next step should be. The doctors nurse said not to worry as long as I was not sick. Should I be worried???