So tired already!

Okay so I am totally feeling stretched out already. I am only 19wks and I feel all tight in my stomach. Well, after I had C there was still some loose skin that needed tightning and now it is starting to become a belly...but it is still really loose down low, but as for the top up by my ribs I feel all stretched out. I am definately carrying high and I hope my belly can handle two babies but geez! I still have half a pregnancy to go and am already having a hard time sitting down and getting up. I was alot stronger with C's pregnancy and I hope that this doesn't hurt me when the labor hits. I have started trying to walk and slightly stretch (can't do it much because of the twins) but I really don't want to be exhausted 15min into labor. I get all tired from walking around stores and feel like I am gonna be "waddling" in a month! And this weather isn't really helping me with my walking! Gosh! I hope I can still stand in 4 months!