i feel alone and really sad i don't know what to do

i feel that no one want to talk, sit, play with me i feel pain in my heart that no one ever felt it before everyday is more dificult to hold it in my back.
everyody tell's me that i'm crazy of thinking that,but they just say that because they don't see what they do to me i feel so sad that i don't want to do anything in the classes but i'm afraid of telling everybody the true of what i feel so if you feel the same coment something please.
that's it.
bye.