I have recently got my fourth concussion, the nausea and the spinny feeling seems to be worse, will gravol help?

Diphenhydramine: should be used with great caution if at all. It stops working after a few days and increasing doses can cause hallucinations, confusion and even death. There is an increased risk of seizures especially in young people. You need the specialized care of a head injury specialist. 4th concussion? Are you a gladiator? I hope you are not planning on playing hockey real soon. (Gravol is a Canadian med)