has your Doc checked your T3 and T4?
As you have been on amoxicillin and everything has come back normal, it is unlikely to be a bacterial infection.
Antibiotics are only effective against bacterial infections, they do not work against viral or fungal infections.
Do you have any other symptoms apart from the fevers?
Tylenol is a pain reliever and it reduces fever, but why were you taking the Ibuprofen for?
Ibuprofen is an anti-inflammatory drug. It can cause stomach problems so should be taken with or after food. Sometimes a doctor prescribes stomach medication to protect the stomach from the Ibuprofen. Ibuprofen can also cause allergic reactions.
Personally, I would take the pain relief medication as directed on the packet or how your doctor has told you. Drink plenty of fluids, soups, jello. fruit juices. Make sure you drink so you do not get dehydrated. Keep of milk products for the time being.
Take cool showers to cool down. If you are bed ridden, is there someone who can sponge you down with a damp flannel to help bring the fever down?
Your profile says that you are male. I have known it to be wrong in the past, so is your profile correct?
Wishing you a speedy recovery.
It could be your thyroid or anemia or an infected tooth. See a dentist and also have labs done at your doctor's office.