I"ve done craft shows for years....and yes, spring shows are always lower in income than the fall shows...but, if the promoter didn't do her/his job and do plenty of advertising, the show is doomed.
Take a photo of your display...Analyze your photo and be critical...BellaBoo is right...marketing is the key. Never have things just displayed flat on a table...an item has to catch the customer's eye as they are walking...they don't walk with their heads looking down on a table.
Try another show...this one could be a fluke.
Good luck...