Need really really good advice so my friend will stop treating me like crap?

were both juniors and have known eachother for years now and shes always treated me diff than others but ive never known why. she used to have terrible acne and is overweight but i never say anything unless its encouragement. yet shell comment on my few pimples and other small things .shell compare tests and when she very rarely does better than me shell rub it in my face. she has her permit and she says stupid crap like: my mom says i park better than you do. im thinking WHO CARES.. im the only one out of our friends that has a license and she always asks me to do something. which is fine but im not big on going out so i usually say no unless it sounds fun.(she will begged me to go to this "haunted" place several times which is 45 minutes away. and wouldnt stop after the first so i ended up taking her and other friends she invited 3 times) then she asked me to go once more (4th time) and i said no way cause its not even fun and nothing interesting happens and she said that was stupid and got mad.. she will seriously beg me over text for atleast an hour to do stupid stuff (like tag cars, "ghost hunt", tag peoples cars)and say how i am lazy and never wanna do anything with her anymore but do with other friends. and sometimes i give in to her begging which makes me feel used. she also acts like im the shy and insecure one but when she gets a "boyfriend" who she will only text and make excuses not to hang out because shes too shy but she wont admit to it and she acts like shes so grown up to have a boyfriend yet she cant even hang out with him! she does several other things but im just gonna stop here. and i cant say were not friends anymore because all my friends are hers and i cant have no friends cause i cant stand being lonely.. soo what do you guys suggest i do to make her stop treating me like ****??