Struggling with Breathing Exercises for Anxiety Relief

Hi everyone 👋 for as long as I've been dealing with severe anxiety I've been told to do breathing exercises to help, and it's touted as kind of a miracle calming technique. I don't really seem to get the benefits, though. I follow guided breathing exercises a lot and I don't feel much better after. I think one problem I have is that I really struggle to breathe with my stomach/diaphram. I've tried doing it laying down, using my hands as a guide, everything they suggest but I can't get my breath to move anything below my upper chest.