Ladies!!! I need help/advice my almost 6 month old HATES Tummy Time!!! I mean HATE IT!! ever since he was a baby baby... he screams to the top of his lungs and he won't roll over but he will lift his head... is he behind?? Should I be concerned? I tried him laying on me I tried laying him on the floor with covers and his favorite toys. And he will not do it.. He will sit but he absolutely won't roll and no tummy time