trans and clutch problems

[JudgeFudge]

i have a 2000 mustang gt it had a auto but i swapped in a manual. its been running fine for a couple of months however recently i have been having a hard time getting out of third gear and into fourth. i adjusted the cable as much as i could and now its having a hard time even getting into gear i have to push the pedal a couple times to get it to do anything please help.