i have had a severe flu virus for last 3 weeks and am so fatigued and weak and glands in neck are up and down all the time. i am seeing my gp this afternoon . i want to demand to have some blood tests done. as do not seem to be getting any better. i am on 50 mcg of t3 prescribed from gp but i feel i need something else. have all the the symptoms of underactive thyroid. hot one minute, cold the next. dry skin and severe fatigue. i would like to know if i need any more blood tests other than t3, tsh and t4. i feel so ill. do i need antibodies test?