Here are some possible meanings of "overwhelming":
* Very strong or intense: This is the most likely meaning in the context of the sentence. The eagerness to work again is so strong that it's difficult to resist or control.
* Causing someone to feel powerless: This meaning also fits, as the person may feel unable to resist the urge to work again.
* Extremely large in amount or number: While this meaning could technically apply, it's less likely in this context.
Therefore, the best meaning of "overwhelming" in this sentence is "very strong or intense".