Here's someone who's very experienced with taking lithium! I wouldn't worry too much about drinking liquids, in fact, most people overdo it and end up with sub-therapeutic blood levels. Just your average 8 8oz a day is plenty unless you're working out or doing anything that causes you to sweat a lot...then you need a little extra. Also, while you're titrating your dosage your doctor will order blood levels to monitor you...and get you up to a therapeutic level.
It was a great medication for me at controlling my symptoms and with no side effects. A medical hospital mix-up put me on Depakote which just isn't cutting it all...it has almost no effect on my depression. Can't wait to get back on my lithium!
You're not alone...I'm BPII, agorophobic, vehophobic, and in Chapter 7 bankruptcy!
Best of luck on your journey!