I think you had such a full day doing so much for others and had so little time for yourself, and also you just felt like you were not even respected or appreciated for all you did.

When it comes to this man you are helping, perhaps it would be better if you helped him to find someone he could pay to do his lawn for him. Yes, he did help you years ago, but, that doesn't mean you should be sacrificing yourself for him to the extent you have been doing. You deserve to have time for yourself instead of giving up so much of yourself.