What Causes Dizziness While Standing After A Second Discectomy?

I had my second discectomy on the 12th of October and since then every time I stand up I get a very dizzy sensation and have fainted a few times I occasionally felt dizzy when standing up before the surgery but now it's worse would this have anything to do with the surgerys? Also there is a history of vertigo in the family and inner ear problems not with me though I'm 16 if that means anything. Thank you