How can I save my relationship?

My fiance and I had twins 11 weeks ago. Our relationship has been suffering since. Besides normal disagreements and rifts we have to take care of our children. We are sleep deprived and angry at one another all the time. I love my children and hubby to be with all my heart. I really want us to be a family. Had anyone else had this problem? Is it going to end? Or what can I do to change things? I feel like we should be celebrating our miracles...so what's going on?