Period/Discharge?

Well i'm 12 and i have been discharging for like...ever! i think it has been at least 8 months since i started. my mom has said for like 3 months i should be getting my period soon and i really want it. but it still hasn't come! i went to the doctor because i was having unusual stomach pains but the doctor said it was gas pains. like not farting gas but something else, and he said it could be some of women hormonal changes February of this year. so like 3 months ago. i still haven't gotten my period. all the other things have come. like , and i shave down there and i shave my armpits and legs too. the discharge comes every single day during school hours. its yellowish and sometimes a little rusty color. like a mix of brown and red. once i got so much of the rusty color my mom said it might have been my period but that was april 1st. and i haven't gotten anything this month. please help! i really need to know whats going on! don't tell me: "You really don't want it!" because i do!