Why do I feel guilty?

I love the man I'm dating. And he is really sweet and loving. But for instance today I got hurt (not too bad but bad enough to call out of work) in a horse accident and he told me to go order myself pizza but he'll pay for it.
I really don't know why this makes me feel guilty. Like I know he loves me and that he cares. But is it because I make less money than him? And I know I can't pay him back? Is it because I wasn't able to do it myself? Why? Like believe me I'm thankful and all and happy he did that. But why do I feel guilty?