Refusal for doctors help?

I am a 13 year old girl and am greatly concerned by the fact that there may be a disorder of some type worsening my ability to analyze ,as well as comprehend very basic things from my education to my social life. I constantly need to be reminded of things, as i can forget a whole day. I know for a fact i am not sleep deprived or hypoglycemic. This cognitive impairment may ruin my chance to success. I feel as if im a moron every time i study, because i know i could get it,andi would forget completely the next day. I can hardly do simple things and (as to be expected)people treat me as my actions portray, a moron. Its getting more intense. Ive told my parents this and have even broke down crying. My parents demand its my diet and my physical life.I have put myself on a strict diet solely for the purpose of enriching the vitamins i supposubley "lack" andi have started exersizing constantly, its not helping I have told them this.I have gone to extremes in the past to get their attention. My parents have given me a deep sense of agoraphobia so i wont walk over there. Their friends mock me and tell me im making it up (my parents know but they figure i can stand up for myself, i guess).My friends think im slow. i guess i am seeing as they are slowly drifting away. I cant form oppinions. I know i sound pathetic No one lets me go check with the doctor and they even shame me. At this point im afraid to bring it up again. Is it worth bringing up?