[tptacek]

That's not quite true in the US. Whether or not you ask to be "committed" (a word you should not use), admitting yourself to the ER or a mental health facility will likely remove most of your control over the situation and will indeed curtail your civil rights.

But if you have to ask whether you should admit yourself to a hospital, do it. If you admit yourself voluntarily, you'll have the option to leave within days, and during those days, you won't have to worry as much about the consequences of your own actions, which by itself can help clear your head.