I would be careful how and if you drive in the near future. The letters can be very slow. Some people haven't found out that their license was suspended until they were pulled over, and then it becomes a much bigger issue.
You might want to check and see if your license has already been suspended before you are pulled over for it.
I'm not sure if ignorance would be a defense in this situation.
In addition to being slow the ministry doesn't always have the right address to send to. I've also heard people complain that they never received said letter of notice of suspension. My coworker was unknowingly driving on a suspended licence when he got pulled over for a seatbelt issue and he was looking at jail time for driving on a suspended licence. The crown wanted to make an example of him because in our region there is a lot of driving while suspended. Ignorance is NOT a defence.