I woke up in the middle of the night wanting to drink something. Is it allowed?

After washing Negel Vaser you may drink. There is no need to say Birchas Hashachar beforehand if you will be going back to sleep.

See also here:

If one awakes after Alos HaShachar and will be returning to sleep, can they drink or eat then? Or do they need to say Brachos first, because its after Alos Hashachar?

#12009