When I was 11 years old, I got a concussion ice skating, got really sleepy, nauseaous, and had to go to the hospital. Doctor's verdict? mild concussion. Two weeks ago, I got a concussion at Keystone doing a leading tail 5 that turned into a corked out shit-show when I missed the grab. I lost all short term memory for like 25-30 minutes and then was otherwise fine, despite feeling like a was buzzed the rest of the day. Doctor's verdict? full on concussion.
The point I'm trying to make here is that concussions can have many different symptoms and can affect you differently each time you have one, therefore, it's best to go to a doctor to have he or she a) verify it's a concussion and b) take a CT scan to check that there is no bleeding or trauma within the cranium. Also, regardless of whether you take this advice or not, do not go skiing again for at least another two weeks. If you hit your head again within that time period, you run the risk of getting what's called "second-impact syndrome," which is basically brain damage caused by smacking your head while it is healing from a concussion. Shit like that can put you in a coma, permanately impair your brain function or kill you. It's a bitch, I know, to keep off snow, but totally worth it in the long run.