If I remember correctly, acetaminophen is simply Tylenol.
And if you're taking 12 tablets of it, you're overdosing which is dangerous. It shouldn't be giving you those crazy symptoms (so you either took something else or it's all in your head) but it will lead to high liver toxicity which could kill you.
Though, if you're getting shaky and jittery like that, maybe it wasn't pure acetaminophen. It probably had codine in it. (Oh the label, it will say "-COD" or something similar) If it does have codine in it, you're in trouble and could have a stroke or a heart attack and should go to the ER to get your stomach pumped.
Why are you taking 12 of anything? Maybe you need to see a therapist too.