Left the gas on for three hours at 12 weeks pregnant — will it hurt my baby?

Has anyone dealt with accidentally leaving the gas on from the stove? I had been in it for three hours when I started to get a headache and noticed I didn't turn the stove all the way off. I'm 12 weeks pregnant and deathly afraid this will end up hurting my baby. Also I am letting my house air out by open doors and windows while I'm out in my car so yes I'm safe