No sleep is torture.
You shouldn't give water at 6 weeks.
I think you need a survival plan, it sounds like Bubs still has some day night confusion, which will end soon, I promise.
Do you have a partner? Could he or she do a shift until midnight? Enabling you to go to bed at 8 and get at least 4 straight hours. And then they can take over any wake ups after 6?
Then they get at least (but likely more than) 6 hours straight, and you get 4 hours straight at the start of the night and then even if you have an absolute bitch of a night, you can get a quick nap in in the morning.
For day night confusion, get them out during the day. Treat night feeds differently to day feeds.
I don't really talk to my baby at night, I get them up, feed them, change them and put them back I the cot. I turn on as few lights as possible.
During the day I chat, sing, get them dressed, open the curtains etc. make a clear delineation between night and day.
Good luck hang in there