There are several reasons that make your vision blurry when you wear contacts. First, you may get the wrong prescription. Second, you may have them in wrong side out. Third, you might not clean them well. Finally, you may put them in wrong eye.
No, it is abnormal. Make sure you didn't wear your contact lenses of the opposite side, maintain and clean them in proper way. If you can ensure all of these, then please take your lenses back to the place you bought them to check if they are prescribed accroding to your prescription or there isn't any scratches on them.
If you get your blurry vision whenever you wear your contacts, then it may be something wrong with the prescription. You should take your contacts back to your doctor and ask them recheck them for you to get the right contacts.