Can someone tell me how to relieve my baby’s gas and constipation?

My 1 week old just started spitting up all of her formula after I feed her but only in the mornings. Also, she has been having trouble pooping for 3 days. I had to insert the thermometer into her anus to make her poop, and she did…3 times…one right after the other. She cries every now and then and gets a painful look on her face. She pulls her legs up and it looks like she is trying to poop, but can’t. Could it be the formula I am feeding her or is this normal with newborns?