I've been dizzy for 23 days straight with no relief?

Okay, so this kind of a long story. On black friday, I came down with a cold, which usually make me dizzy. On that same day I also hit the top of my head really hard. I went to the hospital and they said there's no signs of brain bleeding or anything like that and diagnosed it as a "mini concussion" and that symptoms should disappear soon. It's been 23 days and I still feel dizzy and it gets worse every single day. I can't do any of my school work because of how bad it gets. My head feels heavy and it gets worse when I get up and walk, I even fell on the ground a few days ago because of how unbalanced I was. I've went to multiple doctors, had blood drawn (which was normal), everything, and they send me home but I still feel dizzy. I just want to feel normal again but it feels like no one's helping me.