I understand where you're coming from. My UC symptoms started right after graduation, and it seemed that none of my so-called friends cared. They knew I was sick, but most of them never bother to ask how I was feeling, what was wrong, etc. The latter and the changes with going away to college made realize that my HS friends weren't going to be lifelong friends. However, I have a friend here at college who'll always ask if I need anything if I'm sick.
Molly, I'm sorry your co-workers aren't supportive, but you always have support here!