Can you help me understand the Earth's spinning?

Okay, so the Earth is constantly spinning and we don't feel it because of gravity or something. My real question is what is the Sun doing while we are spinning and orbiting the sun at the same time. Why is night and day 24hrs instead of say a constant flicker of light since our orbit determines the day and night so how does constantly spinning influence the sun's light on us? I am confused. I hope my question makes sense.