Dr. Jace and Mr. Hyde

I think we might be going crazy.

I really need to hear, "it's totally normal, it's his age, he's going through a phase, this stage is going to pass, etc...." It's as though he turns into an entirely different child from time to time. Sometimes he is still the sweet, loving, fun, spunky little boy that I know, but now, at the drop of a hat, he can instantly transform into a terror. It's like he woke up one morning and decided to be a spoiled brat. What happened?? He is 21 months, and I know they call it the terrible twos for a good reason, but this is really extreme. He refuses to eat (that's been going on for a while, but now he is on a strict peanut-butter only diet), he will NOT go to bed, he spends an hour (at least) being put back and back into bed. He's started hitting and kicking and the daycare has mentioned a couple times in the last few days that they are concerned about his temper tantrums because he throws himself down and bangs his head on the floor. He still won't talk at home, but the daycare swears he talks there. He has probably ten or fifteen words that they say he says, and even some two word phrases like, "give five." I can't even get him to say Mommy at home anymore, if I try he throws a fit. We can't take him out anywhere anymore because he is into everything and thinks nothing of throwing an all out, rolling on the ground, kicking, screaming temper tantrum in the aisle at Wal-Mart or outside on the sidewalk. What am I supposed to do? I am trying to be firm and consistent and not give in to his tantrums, but how am I supposed to get anything accomplished? He can open doors, so I can't leave him in his room to throw a fit. Yesterday, while I was making dinner, he would lay on the kitchen floor kicking me. When I wouldn't let him kick me, he took his shoes off and threw them at me, when I took his shoes away, he started hitting, and when I wouldn't let him hit me, he beat up the refrigerator. I kept trying to put him in his room, he kept running back out. I have to make dinner, I have to do homework, and in the evenings, I have to make sure he stays relatively quiet for Thomas's tutoring kids. I hate to see him upset at all, I want him to be happy, but I want him to be disciplined and well behaved as well, so how do I find a happy medium? We're a little frustrated with him. Any suggestions?