Why won't he sleep?????!!!

We are going on week two of Sawyer's sleep disturbances. Every night at approximately 10:30/11:00 he awakes and cannot get himself back to sleep and he is stubborn and strong-willed enough that he can outlast us all with his loud wailing. He will thrash and yell and cry "MAMA!!" at the top of his very loud lungs. He does this repeatedly (about every half hour) until 2:30 or so. I have done research and I know it is not night terrors (although he does thrash around--but he is very much lucid and calms down the minute I come in). He used to be such a great sleeper. After enduring Liam's initial first three months of colic and then later his horrendous sleep pattern (which I blame myself for) for two years, I promised myself that with Sawyer I would do everything by the book. By 6 weeks I was putting him down in his crib awake and he became a sleeping pro. We have no problem GOING to sleep--he is more often than not happy to be in his bed and goes to sleep a chipper fellow. However when he wakes...he is a loud and angry banshee baby. He says "Mama! Rock??? ROCK????" He wants me to rock with him--which I would do but only for a little bit. I would tell him-"we can rock, but only for a few minutes then you have to go back to sleep like a big boy". I do this and he yells and thrashes around the minute I lay him down. He settles himself down and then we repeat the drill a half hour to an hour later. Last night I decided there will be no more rocking. I just go in, tell him to GO TO SLEEP! and then shut the door and listen to him wail a bit and then repeat the drill a half hour to an hour later. It is EXHAUSTING for everyone. No one is getting a good night's sleep and the less collective sleep we get the crankier we all become. Today I found myself coloring a rather ominous looking T-Rex with Sawyer and I told him if he didn't start sleeping at night Mr. Sharp Toothed T-Rex would eat him. Actually based on my current rate of exhaustion, if he doesn't start sleeping at night *I* might eat him.