"Off" switch

Holy crap, I wish there were some kind of "off" switch for my brain. I just CANNOT LET GO. Whilst my body morphs into something resembling a sloth (a sloth that spends waaaaay too much time on the Internet, drinking Diet Coke and eating crap, that is), my brain runs on, a hundred miles an hour, non-stop, all day, every day and (particularly) every night.

It's driving me batshit, I swear. I've got to the point where I just don't know how to relax. All the time, in my mind, I'm having imaginary conversations. Sometimes, I'm having conversations with people that only exist in my fantasies (these can be kind of nice conversations - I feel appreciated and loved by these wonderful people, but the return to reality is rather brutal as a result). And sometimes, I'm having conversations I would like to have (or would like to have had) with real people. The latter are often ranty in nature, which does nothing to help calm me down.

I seem to have a gift for only finding the appropriately biting response to some kind of irritation or put-down once it's actually too late.

I make lists in my head, lists of things to do, planning out the order in which I have to do them. I run through all kinds of useless information, often involuntarily (like counting the number of steps up from my part of town to the centre of town (104, if you're interested) (which I know you're not) (but I'm telling you anyway because hey, if my brain is going to be filled with useless crap, yours may as well be too)), but sometimes just as some kind of test. Perhaps my mother's slowish-but-early decline into total dementia is behind this constant need to test my brain power. Or maybe I'm just certifiable.

Whatever. My brain is always in full systems GO! mode, whizzing and whirring like a crazy machine from a Tex Avery cartoon, often waking me up at night because of a thing I forgot to put on my list. Or a thing I forgot to do. Or whatever.

I suspect I'm headed for some kind of heart condition - my stress levels are always high and this brain-whirring thing can be damn disturbing. Especially when I'm still writing out lists, or crossing stuff off lists, at 3 in the morning with vision so blurred I can barely see the lines on the paper.

Can anyone tell me where the goddamn "off" switch is?