Full-time spirit and part-time pay

This expression refers to someone who has the performance, mentality, work ethic, and mindset of a (good) full-time employee but unfortunately has the pay of a part-time employee (as that is what they technically are).

I go above and beyond work all the time. I love it so much and hate it at the same time. It is such a complicated relationship I have and the situation has just really made me realize that I have a full-time spirit and part-time pay. It's truly so unfair!