Drinking soda during pregnancy

So I drink like maybe one small can of Diet Coke a day some days I only drink water. My problem is that both my mother and my mother in law act like I'm the damn anti christ for it. I've done reading online and everyone says it's ok and not going to hurt anything. My question is did/do you drink Diet Coke during pregnancy did everything come out ok or is it really that horrible? I really just want to know if I can tell them to stfu honestly like they will literally yell at me like I'm a child and I'm done with them.