worthless.

I'm seen as a cheery person, but I use humor and optimism to mask everything. I'm on a ton of meds, have depression, ADHD, OCD, anxiety, social anxiety, and several physical disorders. I've been bullied from a young age, and it doesn't stop. I'm lucky to have friends that support me, but sometimes mean comments get through my tough shell and I feel like I mean nothing. I don't know what to do. Why do people treat me like this for things I can't controll?