I can't say it happened to me as intensely - or, if it did, it certainly hasn't lasted me a couple of weeks :D

But I do happen to enter a flow state, and I tend to notice I literally feel sick by the time I finish writing something.

I have entirely neglected to stand up, drink water, eat, or give my eyes some rest for longer than I should have. That's unpleasant enough, to say the least.

Can't imagine what it would be like for words to gush out of me for weeks and feel the need to write even on toilet paper! :)