I wouldn't be awful if I didn't have the worst slice in North America.
Yeah, that is a common problem that I think most of us have faced. It's most likely your club-face open, which indicates you're not turning your wrist over. It's more common with the driver.
Lots of youtube videos out there to show how you can correct a slice, that is if you have time to head to the range. It will take repetition to break your old habits.