I feel where you're coming from, seriously (i'm looking at you, item art), but honestly though, I feel that this kind of work for us is a labour of love. We work partly for the money, yes, but I also strive to stretch myself and draw things I wouldn't normally, especially in items and npcs, and that advances my own art. I'm sure it's similar with graphics where you can think of new ways to make more interesting works.
Taking a break is a fantastic idea; like Bexxy said, it's really important to step back and take a breath, glance around at what other people are doing.
I constantly think about readjusting my prices, making them higher. If potential buyers truly want my art and are serious about creating an eye-catching environment for their site, then they will work well with me and understand my needs. If not, they're just another wishy-washy pet site owner who thinks we don't spend 2-5 hours every day (more for others, I'm sure), doing what they used to love.
tl;dr i know how that feels bro 8(