I (28F) have Crohn's Disease and Hashimoto's, both of which can cause problems from time to time. I started a new contract job that's short term and remote and luckily my supervisor seems nice and easygoing. She told me initially that my schedule was flexible, as long as I got done the work that I need to complete. Today, I had a meeting with her to see how it was going and I said that my Crohn's is acting up and I'm in pain and that I'll probably be slower and she said that's fine and to take the rest of the afternoon off.
I was talking to my mom (66F) about this and she hasn't worked since the 90s, but she's very rigid about working. She said that I should never tell my boss that I'm chronically ill and has discouraged me from acknowledging my health problems on job applications. She says that if I tell an employer I'm unwell, that they'll immediately think I'm looking for ways to slack on the job. She then said that I'm not unique because lots of people work when they're in pain, and that she would often go into work even if she was sick. She also doesn't understand the fatigue I get because I have these problems so when I do talk about being tired, she doesn't get it and says I'm lazy.
I really don't think I should have to force myself to work when I'm not feeling well, and I'm not really sure this is actually what the working world is like nowadays. When I tell people, they're generally fairly understanding. I generally do tell people because I like to be transparent with what's going on with my health and how it relates to my work, but when I tell this to my mom, she doesn't listen to me. She's very stubborn and rarely changes her mind without actually experiencing something herself. My dad generally agrees with her, but he's owned his own business for nearly 30 years, so I feel like he doesn't really understand my point either.