Is it selfish to not let others copy off my work that I worked so hard on?

Why don’t you just do the projects by yourself? Your classmates should be earning the grades, and ultimately the degree that they will be receiving upon graduation. You sound like a really hardworking student and your classmates are treating you like a doormat. Unless you plan on walking across the stage for them, you should probably start working alone or getting your teammates to pick up the slack.