Go To Sleep, Say Good Night

Last night I got my son into bed at a most reasonable time just before 8pm and he slept for about an hour and a half just fine. I washed dishes, picked up the house a little, and took a shower. When I got out of the shower and the sound of the water running was gone I could hear him screaming in his room. Chris fell asleep on the couch, and didn't hear Ian crying. (Huh? He must have been REALLY tired.) So I rushed to dry off and went to get Ian. I found him sitting up in bed with his feet out in between the bars. I don't know if he was just hanging out there to cry or if he was crying because he was "stuck" there. So I got him up and gave him a bottle thinking I could lull him back to sleep easily. HA! The little turd would not go back to sleep! I rocked him. I snuggled with him in our bed. I tried to tire him out playing. We rocked some more. He screamed. He wiggled. I wanted to cry. Finally he gave up and went to sleep, and I fell over dead tired at 11pm!!!! What a night. I don't know what I am doing wrong that my son just won't go to sleep...I feel like a failure. We have a routine. Dinner. Playing. Bath (every other night due to his dry skin). Pajamas. Rocking. Then when he is asleep I put him into his bed and he is suppose to stay asleep all night (or at least until an ungodly hour like 5am, which I could deal with). Why can't my little boy stay sleep in his own little bed?