Relax and breathe, you'll be fine. And you've got a zillion people here to help. My doc gave me liquid pain medication but other than that I was back on pills by post-op day 2 with no problem. I was told if I had any issued to split them (as long as they aren't time release) but that hasn't been necessary.
Yes, you should have stopped smoking a month ago but you didn't know so now is the time to do it. Breathing after the lap band is a bit of a challenge (for the first couple days) and you are going to need your lungs as healthy as possible. I know you're freaking out and probably wanting to smoke twice as much as usual but for your own good please don't!
Again, every surgeon is different but it appears fairly common to have 2 weeks full liquids after the surgery (I had 24 hours clear liquids then full liquids after that). My surgeon requires you to drink 64 ounces of half juice (100% juice)/half Water a day. Everything else I was allowed to eat was essentially sugar free and I found if I didn't do the juice I got weak and shaky (the first week). With you being diabetic (I assume from the metformin) you're going to have a challenge keeping your sugar stable and you really do need advice from your doc. I highly highly HIGHLY recommend this surgery, but if you aren't comfortable doing it so soon and not having answers then by all means don't do it yet.
Good luck! Fingers crossed for ya!