New born babies are like that. Don't worry..as baby don't know how to latch and too small to suck... they take time. As they grow, things will be fine. While latching..when baby will sleep...slowly remove your nipple. If baby tries to get up... Rock baby or tap and make him sleep. New born can't differentiate between day and night. It's just the comfort and warmness due to which...they want to stick to mom all the time and want to latch always.