Manik99,

Sorry to hear that.... I don't know what kind of emergency it is, wish it is not family one. Whatever the emergency is good luck in dealing with it. Our best wishes are with you.

Ok, here is what you have to do. Your problem is not academic it is more administrative. You should immediately go to registrar's office and ask him/her to withdraw you from this semester and register you to next semester, all in accordance to your situation. I bet you they will hear you, if not then just withdraw your class and go to Nepal and be in touch with your advisor throughout your stay in Nepal. Most of the registration in US is online. Ask your advisor to provide you with the pin to register and register from Nepal.

If I were in your shoes, I would do what I have advised above.

Again, good luck!!!!!