Congrats on your twin news!!!
If you look back to February on this board, I wrote a strikingly similar post when we learned of our twins at the "routine" 18 week ultrasound -- I think I was in shock -- real, serious shock -- for several weeks (all I could say, again and again, was "Holy sh*t" -- this from a person who doesn't curse very much. I just couldn't get beyond that phrase). The women here are amazing and gave me lots of good advice and encouragement -- so you already have a great resource.
And once that initial shock wore off, I read too much (add my name to the list of those loving Dr. Luke and Elizabeth? Noble's books) and started to worry worry worry about all that could go wrong. Now, I am 31 weeks pregnant and finally the excitement is starting to sink in -- what an amazing miracle it is to have TWO little ones growing and becoming people inside of you.
I can't give any advice yet on how life works with two newborns, but as far as pregnancy goes -- eat a LOT and rest a LOT and drink a LOT of water. When people offer to help, take them up on it. Even if it's stuff like folding your laundry, taking an older child to a park, making a meal. It's hard to ask for help but I have needed it so much already in this pregnancy.
Also -- go easy on yourself. I was frustrated that I wasn't able to do as much as I could with my first pregnancy, that I would get so tired so easily, that seemingly "easy" things like going to the grocery store or cooking a meal could completely wear me out. Then my OB reminded me just how hard your body works gestating twins -- he said something that your circulatory system alone works at 95 percent just sitting when you're expecting twins (I could be remembering the details wrong, but you'll get the gist of it) so any time you try to do more, of course you're going to get tired. That helped me be more gentle with myself and not expect as much of myself as I usually do.
Finally, check out a local twin club. I didn't click with a lot of the mamas there (very pro formula, CIO, etc) but by paying my $25 a year dues, I have a card that gets me 10 percent off (or more) at several local stores for baby supplies, etc. They are also a good source for hand-me-downs, etc. that you might need.
Congrats again. And welcome to the club