I am trying to replace a light switch in my bedroom.  Home was built in the late 80s. When I opened up the electrical box behind the switch I discovered TWO 14/3 romex wires coming into the box from the top.  There are also three sets of wires leaving the box through the bottom. I assume these go to outlets in the room.

I've got one 14/3 wire coming from the power source and one 14/3 going up to the light, giving me a total of 8 wires.  2 black, 2 red, 2 white, and 2 green.  I didn't think this was a three way switch.  But I'm at a loss for what to do with all these wires.  Will it work with a dimmable switch or should I use a 3 way switch?  If I use the 3-way how do I utilize all 8 wires and still leave power available for the outlets below.

Please help!  Thanks!