Gave birth 2 days ago, no milk

Brittany
I gave birth 2 days ago. It will be 3 in about 4 hours. I don't think I have any colostrum for the baby. She nurses for 4 minutes, starts crying and I can't squeeze any milk from the breast. I called my lactation consultant and she said to wait it out.  Baby is irritable and I don't know what to do.