I took 3500 mg of tylenol, should i be worried? so far my head pounding, my stomach's killing me, im also slighty gritting my teeth?

You need professional treatment, not your own. Too much medication leads to problematic side effects, see your PCP now.

The maximum dose for Tylenol is 1000mg, and over a 24 hour period is 4000mg (so every 6 hour dosing). Any higher dosing will adversely affect the liver, especially if with alcohol intake. If Tylenol is not helping with symptoms, a clinician on HealthTap's primary or urgent care can further assess and evaluate