First of all, I hate that you are dealing with that. It sounds rough. If you are anything like I am, then you act like nothing is wrong, and come across as laid back, but you aren't...not really. I have a memory about some things that just records what is said. If I am offended, it's hard to let go...especially if someone judges me. For some reason, judgers are the worst. I have had some people say some awful things to me or about me because of being a type 1 diabetic. To make matters worse, I am not skinny...I'm not obese, either...but when you get someone who isn't too smart, and that same person sees your insulin pump...
Bleagch. All I can say is this: don't waste your heart, your spirit, your mind, your time, your energy, feeding the hurt that comes from people like that. Anger and hurt are almost, to me, like creatures that can either live a short life if dealt with properly...or can fester and grow...if you allow them to. Some of those people are scared, some are well...dumb, and some really don't like themselves at all. Other times, if you come across as laid back and easy going, people may try to be your friend or act/say stupid things because they don't really get it...and they feel closer to you if they kid around...
I don't know if that last one made any sense...let me try again. Some of my close friends will all of a sudden, out of the blue, say something strange and joking about me being diabetic...usually, it's because they have heard me growl and gripe and they want to join in somehow.It's weird. I had one friend tell me that it was like what he does with a similar situation...'laugh in the face of the devil.' To him, it felt freeing to laugh at something awful...it took away its power.
I find something peaceful to think to myself when I am around people who are dumb, however. I don't ever retaliate. Maybe that's not healthy, though. Hopefully, there are some people on here who have some idea on how to handle it...better than I do. I usually bite my tongue and then write about it on here, nowadays. If I am dealing with people who are supposed to know better...not class mates, etc. but people I work with, interact with regularly...then I think before I speak...a lot. And then, with my heart about to come out of my chest from nervousness, I confront them peacefully. It is difficult to confront someone without practicing first. I have given up expecting people to get it, though.
Good luck with this. Remember that no matter what you are going through, it will not last forever. How you decide to handle it is what you will live with. I have regretted my reaction to things much more than anything anyone has ever said to me. Wait three days before you react to someone in anger.