The courts will expect you to use your assets, including severance, to pay whatever is ordered. If you cannot support your ex based on current income, they will not care if they believe that you are purposely underemployed. If you can't replace your former income, be prepared to be told to get a 2nd job.
Exactly when did you leave your job and enroll at school as compared to when the divorce was filed? If you were already in school for a year, you may be granted some credibility that it wasn't your intention to be willfully underemployed.
So far as only using current financials to make an award? I've checked through a few sites on UT to see if there is specific language on what financial documents are reviewed and wasn't able to find any specifics- although I only did a pretty quick search. I would venture to say it is unrealistic to only expect current year finances to be reviewed. Courts have a tendency to want to review salary and financial history in the event one of the parties took actions to reduce their salary during, or just before, divorce filings.
I would encourage you to obtain a second attorney opinion.