Am I entitled to OT pay or at least straight pay over 40hrs for work performed outside of my administrative exempt job description?

Your question is more complex than you may believe.  Generally, an employee is exempt or non-exempt.   That is, you usually can't be both.  If you are "exempt" you would not be entitled to overtime pay for hours worked over 40; if you are "non-exempt" you would be.  So, the real issue in your case may be "classification;" do you really qualify as "exempt?"  Generally, the Dept. of Labor looks at the amount of "non-exempt" work an employee does as a crucial factor in whether the employee is "non-exempt" or "exempt".  For instance, a company could employ an accountant whose primary job is to calculate payrolls.  He or she spends 70% of their time doing those calculations.  The calculation work is clerical, not "exempt."  Even though the person is an accountant, the fact he or she is spending the vast majority of their time doing clerical work may render them "non-exempt" in the eyes of the Dept. of Labor.  Also, generally an employee can't be exempt as a "supervisor" or "manager" unless they directly supervise at least 2 other people and are paid not less than $455 per week.  So, in your case, the real question may be whether your position really qualifies as "exempt" under the Dept. of Labor (Wage and Hour Division) regulations.  If it does, you are not entitled to overtime, but if it does not you are entitled to receive time and 1/2 for all hours worked over 40 in a workweek.  Your situation is even more complicated due to the fact your are administering clinical care.  If you have questions I suggest you contact your local Dept. of Labor office.