Hi Nightwing.
Did you turn the car off and on again (yes I know but it does reset the computer)?
if it goes away you should be fine to keep driving short-term but need to get the code read at a garage to find out what caused it. When it happened to me was an airflow sensor.
if it comes back straight away may be more serious and would not recommend driving far, it is a limp-home mode after all and can damage the car if you carry on driving.
Hope this helps,
David