This is the ultimate PMS sandwich. I found it in my Cooking Light magazine and fell in love. It is basically a grilled cheese with tomato and pickles with a little dijonaise spread inside. They suggest Hawaiian sweet bread, but I use sourdough.
Also, a sweet favorite is almond butter and Nutella on dense whole grain bread. If you are really daring and want to try a breakfast sandwich, try two waffles with almond or peanut butter and Nutella spread between.