Mental illnesses, especially today, are being taken in such a way to which they shouldn't. People assume, they make fun of, and immediately turn away from any sort of relationship with someone if they learn that they are dealing with a mental illness. The thing they may or may not realize is, it is not that person's fault.
Yes, you can get help for your mental illness. But what most people fail to understand is that most of the time, you cannot control it.
If you do not struggle with a mental illness, do not judge somebody for theirs.
You are under no obligation to apologize to someone because maybe your anxiety or depression is worse than usual today or your ADHD or OCD is making you do things you usually wouldn't.
You don't have to apologize for taking a day off. You don't have to apologize for crying or feeling down.You don't have to apologize for turning down a date to lunch.
Please, do not feel guilty - you did not choose this. You are not your mental illness, you are not defined by it, nor do you burden others although you may think so. You are more.