HELP!

Ok, anyone with toddler experience, I need your help. I mentioned before that Oliver has been having a hard time sleeping. I think I have reached the end of my rope with it. I was fine with sitting in there for a little while until he was asleep, but tonight he wanted me to rock him to sleep. He finally fell asleep and I put him in his crib and he woke up and cried all over again. So, I left the room and told him I'd be back (hoping that he would fall asleep in the meantime...) and he cried and screamed so loud that he scared Morgan. It was definitely a angry scream rather than a scared or sad one, so I finally threatened to spank him if he keeps it up. It is so hard to tell if this is a naughty, power struggle thing or if he is genuinely scared. I don't want to punish him for being afraid, but I do want to punish him for being demanding and controlling and down right naughty. Last night was awful, too. I went out for a while and he was asleep, thankfully, when I got home, but he woke up at about midnight and ended up in our bed at 1:30 and then he and I ended up on the couch at about 2:oo and he was awake at 6!!! Not only could I not leave him alone, but he had to be physically touching me somehow in order to fall asleep. I was hoping this would be a quick phase because of the no-binky transition, but it is seeming like more. Should I call the doctor? Is she going to just tell me that it is a phase and it will pass and I should just let him cry it out? Because that is tough when he shares a room with a peacefully sleeping baby.
He went through this before when Morgan was an infant. I actually ended up sleeping on the floor in his room a few times. It was almost exactly the same thing, now that I think about it, I would stay in there until I was sure he was asleep and then I would tip toe out and as soon as I did that he would wake up and scream hysterically.
From a purely selfish standpoint, I am getting so annoyed at "wasting" my whole evening sitting in there waiting for him to fall asleep. (I put it in quotes, because I know in the long run, it is not a waste - it's my job for right now.) I can't really get anything accomplished around the house unless I want to stay up super late or get up super early before the kids do. I also don't want to spend any free minute that I do have working on housework. I think I would go crazy. Which is why I'm blogging right now instead of finishing up the dishes or cleaning up the last few toys laying around.
So, faithful readers, what is your advice???