Those tough days

Working for oneself as an artist has its great moments like when you have a show and you sell something or several somethings and everyones telling you how much they enjoy your work and such. However those seem to happen less often than the times you have a show and sell nothing. Then its back to the studio to work some more. Those are the tough days, weeks and months. Going back to work and working hour upon hour on new work wondering if it will ever sell.