5 mth old up every 30 mins....seriously!!?
This happened with my oldest and it turned out to be a food allergy to when I ate dairy or gluten. Once I cut those out, she slept much much better. She never ended up having any food allergies herself or else she outgrew it before she started eating those things after one year.
Those months before I figured it out were so utterly exhausting. Hope you get some sleep soon!