I hate myself for everything...only 14....someone help me un-hate myself?

ok so,im a girl in the 8th grade and cannot wait until promotion!!!so i can get the hell out of there!!!!so my last period was pretty heavy and i thought i had it under control so i wore a pair of khakis (uniform school)and i kept checking every 10sec to make sure it didn't go through..but at lunch i checked and it went through not allot just barley but it was way down and un noticeable and i needed a jacket to cover it so i could go change and i only told 3 girls at my table,,,,and somehow now this one girl who sits at the other end of the lunchroom swears she saw it...but idk if i should believe her or not because she is one of the "fake" girls and she does LOVE to start trouble....and one of the girls i told is telling me that there might have been some smirks..and another thing,im completely separated from my usual group of besties becuz weer in different homerooms and i thought i had one friend but shes acting as though she doesnt care anymore and shes one of those girls whos very kind and shy...i dont get it we were like bffs up untill after winter break wen we got our seats changed becuz we kept talking and shes just ignoring me flat out..i told her how i felt she said tht she is sorry and she says she feels akward around me and she also said tht i was her only true friend...Ok if i am then why is she ignoring me....Really wuts wrong with me why does it seem like the nicer ppl are the more ppl will hate u and the meaner u are the more ppl love u.....someone pleez help me i really am i nice girl....with almost no friends:l