I think salads just slip right past the band. Try eating a hamburger or a sandwich from Subway or something that has a bit more substance. Chew slowly and thoroughly of course That should fill you up. If it doesn't, or if it makes you sick, you need to talk to your doctor. You may want to talk to the doc anyway because sudden weight gain may be a sign of problems with the band.
Remember that 50 pounds is a real accomplishment! Keep working at it and you will lose more.