My Son Has Shivers Really Bad. First Time Ever. He

my son has shivers really bad. First time ever. He sweated profusely earlier. No appetite. Swollen lymph nodes. Headache bad. Weak. Fatigue. achey muscles. Doc prescribed amox/clav 875mg but he is throwing up too much to continue. 3rd day on it. He said if he got worse, take him to ER. they think the swollen nodes are viral infection but the amox/clav is for bacterial infections. What do I do. Take him to ER. He has a hard time drinking anything, but was able to eat a few things earlier that settled ok.