Sleep when the baby sleeps. Seriously. A good nap during the day will do wonders for your ability to cope with night time bothers.
For snuffy little nose:
Warm steamy shower. If she'll tolerate it, pour some warm water on her face. If, like most babies
, she'd hate that, wipe her nose with a soft cloth soaked in a ton of water.
Also, massage the corner of her nose gently, it's a acupressure point for clearing the sinuses, works surprisingly well.
Finally, after you have everything loosened up and cleared out as much as possible, gentle suctioning with a bulb syringe.
That's the order of things that I found worked best, sucking out the snot didn't really help until it was loose and already starting to come out.
As for gas, have you tried bicycling her little legs? It ends up using her legs to massage her tummy. http://www.youtube.com/watch?v=KsXGEoDf_pQ
is the "I love you" tummy massage to help everything move along.
And part of it could just be that she doesn't "get" night and day yet. Continue to keep things as dark as possible at night and get her a bit of sun and keep things generally bright during the day, and it'll help adjust her rhythm. But meanwhile, sleep when the baby sleeps.
Did I mention that you should take at least one nap with your baby during the day yet?