after a half hour drive i parked my car realizing i was out of the lines slightly (dogdey parking

the words Engine Management System flashed up on the little screen followed by the words Faulty,
panicking as females do i checked oil radiator coolent etc which were all fine, however engine was really hot !!
i started the car half hour later and the overheating revving sound had gone but engine management system still flashed up aswell as my service light, i took it for serveral runs around the block only for the service light to turn off and things to go back to normal !!
now am i going completely mad or is this not right !!!!
my car has only done 30,000 miles and had a new cam belt fitted last month with no problems untill now !!
any replys i would be extremly grateful !!!
Thanks
