About 3 inches diameter fell inside toilet bowl, flush is working very slowly, cnt use the bowl after pooping, good only for urinating... what to do?

If it is a glass ball, us a closet auger to break the ball and then plunge. If it is a plastic ball, you can try an auger but may have to pull the toilet.

If not, call a plumber who will remove the toilet and try to remove the ball from the other side. There is a curve inside and it will have gotten caught there ( most likely)

ma0641touched all the bases. Purchase a closet auger and either breaking up or already back out. Good luck, Tom