Am I overreacting??

My fiancé turned on the keroscene heater heat our house so we can save money on heating our home and he tends to turn on this heater indoors here and there. I have told him 100 times I’m not comfortable with that and if we’re trying to save money, I can pay for the heat if it’s such a problem for him. We have radiators and sometimes I just want the nice heat on.

Mind you, I’m 7 months pregnant and do not feel comfortable breathing in that heat with me being pregnant and read online it is dangerous or can be dangerous. I told him kindly that I didn’t feel comfortable breathing that in. He got pissy and upset and he turned it off and was saying I don’t understand anything about heat blah blah blah. He was in a great mood and now he won’t talk to me. I told him I could pay for the heat if he’s so worried about us having to get oil every few months as I have plenty in my savings. I hate to say it but he can be so cheap sometimes and honestly it’s making me so upset as it’s at the cost of me and our baby now. Am I over reacting?