I havnt had a poo in 1 month. HELP!!!?

Please help i always had Constipation since i was young id say when i was 12 and now im 16 normally id wait 2 weeks and id have a poo but i cant seem to have one and when i try it really hurts and it wont come out id scared of that colon cancer thing, please help!!! its been 1 month and nothing i can feel the poo in my stomach and im always bloated after lunch, i don't eat much fruit but i drink a lot of water i really need help. I think im going to die very soon if it says as it is im too scared to tell my mum so what can i do please help me.