Don’t know what to do!

Lyd

My little girl is 8 weeks old and breast fed so the pediatrician told me that pooping only once or twice a week is normal for her. But she seems to strain a lot days up until she poops. Like screaming, crying, farting a lot, can’t sleep. I don’t know how to help her! I don’t know if it’s my diet or what but it’s stressing me out and I’m sure it’s hurting her poor bottom and tummy trying to poop. Also the doctor checked her bottom and said her sphincter muscle was tighter than it’s supposed to be and it could be causing pain to but he didn’t tell me how to help her?