Having a hard time pronouncing big words

Having a hard time pronouncing big words I'm going to school for pharmacy technician and I am having a hard time pronouncing large words such as drug names and diseases. I get made fun of by my peers because I cannot pronounce big long words. One of the reasons why I'm shy around people. Before anybody jump on me, when I was a child I've taken speech therapy ages 5-13, for stuttering, I don't stutter badly like I use to, but I'm still having trouble. I become very embarrassed and hurt when someone makes fun of me What should I do?