What's done is done, so there's no use fretting, but if you haven't already, consider a a bath. Soap at least twice and rinse very thoroughly. See if you can find out what the pesticide they used is, call your vet, and ask if there's anything else you can do. And if you can get hold of whoever did the spraying, I'd want to know what that sign means. Did they spray on 9/3 and are going to again on 10/5, or are they saying keep off until 10/5? And mention they should do a better job flagging that grass (after you get as much info as you can).
