Hair falling out and fingernail problems may also point to a zinc deficiency.

There is a condition, that is inherited, that is called pyroluria.
It results in loss of zinc and B6 thru the urine because of a liver metabolite of heme... complexing these nutrients out.

Symptoms are similar to other conditions like hyperthyroidism, and bipolar. Often anxiety is huge and patients think they are "going crazy".

Here is more...it is diagnosed with a special urine test:
http://www.drkaslow.com/html/pyroluria.html

It can lead to self medication with drugs, and alcohol and there are some estimates that some alcoholics are actually pyrolurics.

While it is possible a flu shot triggered her, she could also be triggered by stress and poor diet if she were pyroluric. People with pyroluria can have normal times and then suddenly display symptoms. College is a big stressor and also leads to poor dietary habits at times.

The treatment is supplemental B6 (best taken as P5P active form) and zinc.(best taken as OptiZinc).