Is my occupation student or full time if I was a student for 5 months and worked full time for 4 months out of the year?

You can use the occupation you had at the end of the year.  The occupation entry is only used for statistical purposes.

Enter social worker for occupation, since that is what you were during most of the 2nd half of the year and will be continuing.

Not listing student as occupation does not prevent you from claiming  a tuition credit, if you had expenses for your last term.

Also, being a student for 5 months may affect other tax attributes. For, example you could still be a dependent*, depending on the other "qualifying child" rules.  That is, having income doesn't automatically disqualify you as a dependent.  Having been a student, in the year, disqualifies you from the Retirement savers credit. 

*See full dependent rules at: https://turbotax.intuit.com/tax-tools/tax-tips/Family/Rules-for-Claiming-a-Dependent-on-Your-Tax-Return/INF12139.html