PhD student lost fellowship 1 week before school starts, what should I do? I am a rising 2nd year PhD student in a US public school. 

I was promised 4 years of funding by my department. Last year, I received a fellowship which covered tuition and stipend. I believe most people get 2 years of funding, so I was expecting it to be renewed. Over the summer, I kept asking about the status of my renewal application and only until yesterday (1 week before next school year) did they inform me my renewal was rejected. The secretary who communicates with me still has not told me why.

The next school year starts in &lt;1 week, and all my classes will be dropped tomorrow if my tuition is not paid. To make matters worse, I am an international student, and if in ~3 weeks my tuition still isn't paid, then my visa will be invalidated and I fear I may be deported. 

I will talk to my advisor tomorrow, but much advice is appreciated. In particular, I wish to know whether there is any standard procedure for this kind of situation and whether I should pay my own tuition first in case of any visa problem.
I wish to know whether there is any standard procedure for this kind of situation


You already have the right answer.  Talk to your advisor.

PhD students should never pay tuition.