98 contour overheating?

1998 contour SE V6. For several months now my contour seems to run hot. I think it happened after my catalytic converter was replaced, but I'm not sure. the temperature gauge had always registered below normal, but now it is consistently at the M or even the A in "Normal." It seems like the electric blower in the engine is on almost constantly (it does go off occasionally). I am very nervous now in the hotter weather.
Should I ignore what the temperature gauge says? Everytime I have taken it to a Ford dealer (even different ones) they say there is not a problem. The car has a little under 50,000 miles on it. Is it a serious problem? If the thermostat is replaced and the gauge reads lower, is that just masking a still serious problem? What should I do to get it checked and/or resolved?

your waterpump may be on its way out....may want to upgrade to the metal impellar w/p and go from there.