Aight I'll tell ya what, from experience.
You inhibitions are not so lowered that you will say every single thing that pops into your head. You can control yourself, I'm sure you'll say somethings that the next day you'll be like... wtf thats the strangest thing I've ever heard.
If your thinking your going to insult someone or get into a fight coz of insulting someone, or telling someone to fuck off and die in fire. That probably wont happen also. The trip your gonna get is gonna be somewhat like your love everybody, nobody is a bad person they all are niiiiice
NOTE: DO NOT, DO NOT, DO FUCKING NOT. Do Any other illegal drugs, NONE. I don't even drink while I'm tripping on E.
Somethings that you might get paranoid about, Your arms may feel stiff, some people I know have this some dont, Myself, I find myself constantly with my teeth clenched, I try to stop but its something I dealt with. Your temperature will go up, drink alot of water, 5-6 bottles of water, most of the time when someone gets to the hospital from E, its dehydration. One of my buddies shakes alot, he can't hold his hands or feet perfectly steady, its not a massive shake but its more than normal.
Your Vision will probably get blurred, all of my buddies did including myself.
Panic Attacks: Every drug will do this, when you feel that something is wrong, ask a buddy be like "Hey man, you feeling such and such?" They'll let ya know they are and its normal. Your heart is not going to blow out your chest, and yes... you are still breathing.
I've never gotten a headache from X, ever. Maybe this is something each person may feel differently. The next day you'll probably feel out of it, much like a hangover but you won't be sick to your stomach. It'll be the whole, I'm outside of myself watching myself do everything.
No matter what anyone tells you, every single thing in the entire world, is addicting. Eatting peanuts? Addicting. Eatting Bananas? Addicting. Eatting steaming piles of shit? Addicting for someone I'm sure.
As for your body physically needing it? Do it once if you so wish, you won't be addicted to it from one time. Physically. If you have the willpower of a fat women in a chocalate house. You'll probably be addicted.
Closing my little documentary into Ex, The important thing is to have a good time while your on it. Don't think too much, just have a good time, you may or may not regret it. But hell, theres only one way to find out.