K.M.
My son got his big boy bed when he was two also and his sleeping patterns changed a little. He became more scarred of weird things like the closet that were never an issue before. After a couple of weeks of sleepness nights and a little talk as best he could about what he felt was wrong with his "new" room, we decdided to take him to build a bear. His dad and him built a "safe monkey" which has a recording of his dads voice saying " hi bud, its dad.. I am so proud of what a big boy you have become.. mommy and daddy love you.. we will see you in the morning." as well as a heart in the chest that makes a heart thumping noise.
Since then we have not had any problems, sometimes at night after he has been laying down for a little while you can hear the monkey talking but he doesnt get up or get scarred anymore.
He takes the monkey with him now whenever he feels a little uncomfortable, like when we went on a plane for the first time.
Good Luck.