When nobody believes you

I am trying to be as nice as possible about this...But my god I hate people who actually think that I am making up this disease. Are people actually that small minded...or are they just badly informed. When my belly is so bloated I look like my sister in law who is actually 6 months pregnant, there's some sort of problem. When I hurt so much I just want to be sick, there's a problem. When my lady parts feel like they are trying to kill me...there is a fricken problem. And yet somebody actually told me that 'Oh it can't really be that bad. You look fine and your not in the hospital so it can't be as bad as you say'. I honestly wanted to slap this person so hard, and make them go talk to a doctor in order to educate themselves. Better yet I should have given them  a million websites that talk about my disease and ask them what they think after reading everything.
I understand that everybody has their own problems, and that not everybody in the world is going to know what exactly endometriosis is...god knows I didn't until I was diagnosed. But that doesn't really give people the right to tell me how I should be feeling. I try my best to keep my chin up, not complain, and go about my days as if nothing is wrong. But that certainly doesn't mean that I am not suffering or that it 'can't be that bad'. I think that maybe people actually just don't give a shit about other people most of the time. So they don't bother to educate themselves on issues, or have sympathy for the things that they don't understand...and that makes me sad. I always give people the benefit of the doubt and listen to their problems when needed. I just wish that the rest of the world could also be like this, instead of being self absorbed to the point of not even trying to understand someone else's pain.