Worried

I'm currently 17 weeks pregnant and work as a Pri School Teacher. Almost everyday I will need to raise my voice and be firm to students. At times, I experienced cramps after correcting students. I'm really worried for my baby and scared it will be shock if I ever need to raise my voice and will be affected by it. As a teacher, I try many ways to address students, but at times, can't be helped and I still need to be firm and raise my voice. Will my job affect my baby's health and growth? I'm really worried as this is my first pregnancy.