No concept of time!

My Lukie really struggles with the concept of time. I'm sure it's a developmental thing but he refers to anything that happened yesterday as last year. Tonight, he told Andy he didn't need a bath because he had one last year. We were cracking up! If only he knew what he was saying. :) The reason this sometimes concerns me is that on days I have been at work and I ask him what he did that day or what he ate for lunch, he really struggles to answer me. I don't know if he just doesn't want to talk or if he truly doesn't remember. We usually have to help him remember and jog his memory and then he starts to remember things. He does the same thing if Andy has been gone and asks him questions. Hopefully he'll start to understand and develop his concept of time soon!