Sleep... I need sleep.

My twin girls have been home from the NICU for 4 days now (3 nights) and I've averaged about 3 hours of sleep each night. They sleep so good during the day, but when night time comes they fuss and whine and seem like they can't get comfortable. I try everything to help them sleep but it doesn't work. They are preemies born one day short of 34 weeks, not sure if that has something to do with it. They aren't my first babies but I just don't remember the first few days home being this hard with my other two. Any moms of multiples have any advice for me?