Meditation and breath work make me feel anxious

When I attempt to meditate and focus on my breath I feel really anxious and I get very obsessive over my breath until I feel like I can't breathe anymore, my chest gets really heavy and I feel like no air can come in and I can't breathe. I have a long standing history with anxiety and I am try to sort through it with the aid of meditation and breath work but my symptoms manifest very physical and I don't know how to not feel them. In the past my anxiety symptoms were so bad that I thought I had a heart condition because of how bad my breathing was. Last night I tried to do a guide breath work session and ended up just feeling really upset like I was just not doing the right thing and I don't know how to fix it. I know that meditation is supposed to be relaxing and if I am struggling this much to relax and being further stressed then clearly I am doing something wrong. So does anyone have any advice for me on how to do better?