popnGEAR,
Keep checking your coolant level. If you keep loosing coolant that seemingly disappears, then yes, you probably have a blown headgasket. The coolant is seeping into the combustion chamber and going out your tailpipe. If it's bad, you may even notice a white-smokey (water vapor) appearance out the tailpipe.
If the leekage is minimal, it's not going to screw up anything - in fact, the water will clean your piston(s). I saw this first hand on my old '85 toyota pickup. I replaced the head gasket myself and the piston that the water was leaking into was clean as could be whereas the others had a thick layer of carbon crap on them.
Get it taken care of, though as there is a possibility for hydro-lock which will throw your rods through the crankcase or bend valves.
- Steve