That sounds so annoying when your reader dies on you like that... I've had similar issues before and and sometimes it's the battery being super drained. Try holding down the power button for a long time & like a minute or so, to force a reset. And make sure you're using a charger that works, maybe test it on something else first.
If that doesn't do it,, check if there's any dirt in the port. A little cleanup might help. Works great sometimes. If it's still not responding, it could be time to think about getting it looked at by someone who knows electronics.
Hang in there, hope you get back to your books soon.
