If you are that comcurned,hire an environmential hazards cleaning specialest to take a look. This isn't a diy job,especialy if it's your first experience and you are depending on the net for training. The contractor's first screwup was not controling dust during demo. Secound and worst screwup was turning the *@!^ air on without special filters in front of intakes.

I watch a lot of home remodeling shows (Mike Holmes, This Old House, etc.). Anything time there is anything with asbestos the removal specialists are called. It is often a big project to remove the smallest amount of asbestos tile or insulation. It is taken very seriously.

However I have never seen anything on these shows when it comes to removing drywall. There is no mention of testing it. The demolition team pulls down the drywall as fast as they can. At best they wear a dust mask. No other protection or asbestos remediation.

I don't want to give bad advice, but I don't think this is a concern. Check the filter and see if there is any drywall dust. If there is none, then I don't think you have to worry about it. If there is, change the filer and inspect the air returns carefully. See if dust has collected anywhere. Then you can decided whether you need a professional to come in to do a clean up or not.