I had taken my clindamycin for strep and I have this "burning" feeling in my throat. What did I do wrong and how long will this last?

GERD. It sounds like you have developed reflux related to the antibiotics. Start probiotics to see if they help. Take a high dose daily for 2 weeks. If you vomit any blood or pass and blood in your stool, see your doctor. All the best. Check to see if your strep has cleared.