Since I am still a student I usually get plenty of alone time everyday so I usually get plenty of time to recharge, but when I do get into situations where there are a lot of people (like going home for the holidays, family vacations, etc) I find myself getting anxious and just very irritable at everyone. If I can't handle it, I just walk out on people and find a spot where I can be alone. Mind you, I am used to a good 15 hours or more everyday being alone so being in a situation where I am constantly around anyone can make me a little insane. I can handle it for a few days sometimes, but other times, not really.
When I was little I remember going on a church youth camp out and I needed space so I got up and walked away--didn't tell anyone where I was going--totally freaked my parents out.
I think what sets off my need to recharge though is just constant people interaction--I can take sensory overload, information overload, over even living in a city or spending time in crowded areas--as long as I am not expected to interact with others. I can be alone around others, but when I really need to recharge, my brain stops being able to handle anything and it won't settle down until I can be alone to just stop everything and think.