I have bad constipation and i'm thinking from from diet should i eat alot better for 2 weeks if no improvement see a doctor recently i've had alot of strain and there's always bright red blood at the bottom of the bowl for last 3 bm?

Constipated teen?: Each person with constipation needs to be sure there is no other disease causing it. If constipation is just due to slow movement of the food and poop through the gut, things to try are vegetables, prune juice, prunes, fiber-plus-water, polyethylene glycol, Senokot or other senna, milk of magnesia, etc... Make a symptom and "laxatives" diary for the doctor, who can assess and help.