Periods!!!

I haven't had normal periods in 6 1/2 yrs until I had my daughter. I'm trying to figure everything out all over again so I'm trying to prevent from getting pregnant, but the problem is that birth control messes me up I had to get fertility treatment to have my daughter due to birth control but then I'm allergic to condoms, but I also don't want to come out pregnant.. so my question is which days are my safe days to have sex and not come out pregnant.. like I said it's all new to me again it's been 6 1/2 yrs. Please don't judge me.