This all sounds way too familiar to me too. Work, girlfriend, hobbies, sleep balance is a bit messed up for us guys/gals in this industry me thinks.
I find that when I'm busy with a number of projects at once (especially when there are a few going live around the same time) I average around 4 hours sleep a night for a few nights running. I do 9am-5pm(ish) where I'm doing some productive work but more client meetings, phone calls, project management, etc. and a second stint from 10pm-5am, which is usually pure design/development and the odd visit to a forum/blog to read and post my views when my eyes start to hurt. It would take me 3 days working 9am-5pm to get the same amount done in one night from 10pm-5am.
It's amazing what you can get done when the phone isn't ringing or you don't have to go to meetings, etc.
Throwing a girlfriend into this mix can really mess up a perfectly good routine!