I've put on almost 4-8lbs

In the past 6 weeks of being pregnant I've gained between 4-8lbs. I'm always hungry!  My stomach feels like I'm being gripped so tightly at times. Any ideas for healthy snacks at work?  Can't always have a face full of food in front of my students though?????.  I need some healthy options that will keep my full and not cause too much weight gain. Any ideas ladies??