Should I go to the ER?

I checked my sugar at 5:30 pm and it was 317 and I took my 5 units of regular insulin checked it at 7:30 it came down to 305 I ate supper had Chinese pepper steak no rice just the pepper steak and a big glass of water and a peach that is all I ate waited to 9:45 checked sugar cause I feel strange after taking the insulin at 5:30 and when I checked it had went back up from 305 to 348 I thought insulin would bring it down I feel funny dizzy on standing and thirst and confused a little what should I do any help please