A.K.
I agree with feeding her right now. She's still young and probably small as a twin. I have twin boys and they just started sleeping at 4 1/2 months through the night. As far as the crying, ignore it if you can. The other one will get used to it and sleep through it too. Mine can sleep now through nail guns, chain saws, sledgehammers, etc. (We are putting an addition on the house) I'm glad I got them used to noise early on.