Severe Pain In My Head With Swollen Glands In My Throat

my name is Jonathan Daniel Delgado, I am a 29 year old male. About a couple of weeks ago i became ill, the glands in my throat became extremely swollen and painful, my body became extremely weak and achey and i was in getting severe unbearable pains in my head. A couple of days later still sick and in pain i went to the emergency room and they ran tests and they said everything was normal and sent me home. After being sick in bed for 6 days i went to a doctor and he ran some blood tests and he said come back if it gets worse, a couple of days later it does get worse and the doctor diagnoses me with strep throat and gives me antibiotics and pain killers for the severe pain. I take the medication and a few days later i begin to get better but i still feel really weak and am having dizziness which was affecting my work. Eventually my throat gets better but for a couple of weeks after i feel extremely weak and have no strenght and im not able to function properly. So that perstists without any getting any better. And now a couple of weeks later the same things has come back with my throat and my head pains and body aches . The doctor told me that he tested my blood for hepatitis , anemia, diabetes, and mononucleosis but everything was normal. Now im on a different kind of antibiotics but im still feeling terrible. I need help please. I dont want to be sick anymore, What could be making me ill like this? The doctors keep telling my bloodwork is normal but something is obviously not normal.