A.B.
It does sound like he's teething, and the medicines could be adding to it. Some say that it's really early for him to be teething, but my daughter was 4 months old when she got her first tooth and still breast feeding. I would try baby oragel and massage that into his gums, or these teething tablet. Maybe even popsicles that will soothe his gums and get some fluids into him. I used the tablet beacause it's easier to administer and no fear of getting bit! And if that helps I would go ahead and try giving him pedialite, or something for dehydration. Good luck!