heating problem, and motor problems

i have a 93 civic lx d15. After driving and i have to stop at a light or somewhere it starts to heat. then when i go it cools back down. what could be wrong. it is also using up all the water/antifreeze in the radiator.

And another thing, when i take off it is really sluggish, then once i get to about 2k rpm it takes off. when im just sitting and rev it up, it revs real slow til about 1500 or 2000 rpms.

any ideas on whats wrong?

possible a blown head gasket...any white smoke out of the exhaust... check for coolant leaks from engine, radiator, cap, timing belt cover... remove plugs and check white part of electrode for greenish color, also check plug tip for signs of corossion from water.