1. Your rat sneezes could very well be the new home sneezes that many rats go through when introduced to a new enviroment... they tend to sniff a lot to take in all the new smells and sneeze because of it. If this doesn't stop within another week you should take her to the vet.
2. You are very early in your socialization of your new rat, and it would seem that she probably wasn't socialized much before you got her. One of my girls nipped me a bit the first two weeks I had her, and I can't even remember when it stopped, it just did, because she learned to trust me. She never nips now, not even when search my hand for food. You need to continue to hold her, but if you're scared you can use a pair of gardening gloves. Also bribe her with lots of treats, and do some research on trust training, etc.
3. Your rat needs a friend. She is probably hunched because she is scared and lonely. Go get her a buddy, and her confidence will most likely double.
4. Girls are hyper rats. More so than guys, and much more so when they're young. She will calm down as she gets older, and even though she may still be quite hyper in a couple months, she will be much better about bonding with you.
Ultimately, you need to giver her time, patience, and understanding love, and she will come around.
