Your son needs examination by a paediatrician and an ENT surgeon. The vomiting may be due to gastritis (acidity) due to the medicines, especially if you have been giving them on an empty stomach. There is a rare chance of the vomiting being due to the ear infection, especially if it is projectile. Very young children can easily get dehydrated and continuous vomiting & ORS use can cause electrolyte disturbances. Anti-emetic (anti-vomiting) medicines (drops / syrups) like Reglan / Ondem/ Emset may be required to control severe vomiting.
Please be extra careful and take an immediate opinion if he looks pale and is weak / lethargic/ not responding well, has a dry tongue or decreased skin turgor (elasticity), has increasing ear pain or headache,