I Feel Like I Have To Poop Extremely Bad And

I feel like I have to poop extremely bad and just can't, I have taken laxatives, pill form and liquid in the last 9 hrs at maximum dosage and nothing has happened and have probably spent 5 hrs on the pot struggling to get anything out. Also I have been drinking some fiber packs that you can mix in water, still nothing. I don't understand why this is happening, I am a college athlete that exercises regularly. I know my diet is not the best consisting of regular fast food consumption, red meats (all meat/ fish) and rice potatoes and macaroni with little to no vegetable and fruit intake but I thought the laxatives would work. What should I do? I am in so much pain. Last month I thought I had apindicitus but just had to poop. Thoughts?