2003 Chevy S-10 Toxic Fumes! ! !

Hey guys, I was driving in my S-10 with my girlfriend. She turned off the AC, and we both noticed a small white puff of air come out of the vents. Then she said "do you smell that", followed by "my nose is kinda burning around the edges!" I too noticed the smell. It was coolant, which I recalled also smelling faintly earlier that morning. I pulled over to look under the hood/car. I didn't notice any leaks, fumes, or smoke. After a little while longer the fumes through the vents began to intensify. I thought it may be r-134 leaking, but this had to be something stronger! It burned our throats, noses and lungs. When we got home and were out of the car, I called poison control and asked what to do about inhalation of "freon". Now, 2 days later we can breath somewhat normally? I have been driving another truck. When I opened my S-10 (the toxic truck) to get something out, I was overcome by the fumes again. After 2days of sitting, what could it be? I checked the battery for a leak, but it was dark, and I couldn't see much. Battery Acid? Cat. Converter? Freon? If it is battery acid, what should I do? HELP PLEASE! Thanks so much, you guys rock!