How long dose a ketamine come down last and is it normal that i can not sleep?

i was in amsterdam on the weekend and i was stoned and we got some coke of a guy but it ended up to be Ketamine the night was chilled out then i went home were i was sick and i was lossing my **** just having a freak out it is now tuesday and i may have had 7 hours sleep i have just started to take vit C and drink water but i am still wide awake to manny things running thru my head can some one help me out im a little freaked out