Sugar Glider Pregnant?

I have a male and a female sugar glider. And I've noticed shes kinda aggravated towards me. She used to crawl up my arm everyday. But i have also been noticing that the male have been licking her and climbing on her back. Also she has been hissing and barking. The male has been more aggressive, he runs around and gets close to the door of the cage. Could she be pregnant? One more thing she looks a little fat. But i cant get her to sit still long enough for me to look to see if she has a pregnant belly or not. Help?