FTM: help!😫

Destiny
I have a one month old baby who is constipated. He was both breast fed and formula fed, but we had complications with the formula. So now he's only breast fed. The formula I had him on had iron in it. I'm pretty sure that's what caused the constipation. Now I'm stuck trying to relieve my poor baby.😫 He didn't have a bowel movement yesterday and so far not today either. I can see him trying to push, but nothing's coming out. I've contacted the closest thing I can get to a doctor for a weekend. And they told me it's just a waiting game. But I feel like I need to be doing something to help him. Because I don't want to keep loading his belly up if he's not going to poop! With the formula he would eat and eat. Then he wouldn't poop, and at one point he threw up. And I don't want that to happen again. So I need help!😬