Hi kl,
Just a small FYI, and as a sort of courtesy to those wishing to respond, it's really better if you put all your questions into one post. Thanks!
As to your questions if escitalopram (Lexapo) can cause your nerves to feel "hyper," this medication can cause tremors and twitching. I'm not sure if that is what you mean by "hyper" or not.
It can also cause CNS headaches and sinus headache. (Either of which can be brought on or exacerbated by photosensitivity, yet another side effect.)
Escitalopram can take up to 4 weeks to reach therapeutic levels in your blood, so I would give these symptoms a bit more time to "settle" down before you got worried about them. If they begin to interfer with your ADL's, I would certainly speak with your doctor, otherwise just do your best to wait them out. Almost every med used on this forum has some side effects and most of them disappear once your body adjusts to the med. My advice? Hang in there.
Peace
Greenlydia