Joshua had something similar last week. Vomiting, high temps even nurofen could not kick out the temp. We rushed Josh to hospital as he became limp (like a rag doll) due to fever! He ended up having a virus and the doctors told us that the fever is a way of the body getting rid of the virus.
They told us to keep up nurofen and put a cool washer on his forehead and neck! They also told us not to keep him to cool (as in clothing) as that is just cruel in this time of year ... just a cotton jumpsuit (rather than just singlet and nappy).
We eneded up needing antibotics for Josh and it still took a whole week to get it out of his system. I hope you get answers soon and that the little one feels well shortly. It stresses you out doesnt it as you dont know how t o help them..poor bubs!