Bullied for my medical problem

At the moment I’m 14 and I get bullied as I have a medical condition and I didn’t really want people knowing but when I got in to high school people started noticing that I was having a lot of time off and when I was at school I smelt a bit and was always changing clothes during the school day. Then I made a really good friend and decided to let her know of my problem and then the next day everyone knew and they were calling me names. to make it worse I had no friends now I have a few friends who are reserved like me my old friends hate me and are always talking and laughing about me but I tend to just concentrate on my school work