URGENT 8 month old severe constipation

Please please help my baby just woke up from her nap screaming, I checked her diaper and she is trying to poop but it is very very large. She hasn't pooped in about a week, we tried ALL the home remedies and finally peed said to try a dose of miralax which I did last night but it doesn't seem to be helping. She is screaming and inconsolable. Is this something to bring her to the er for? She hasn't made any progress in 10 minutes.