Third pregnancy heart rate

This is my third pregnancy and I know well enough that you can be out of breath and have a bit of a faster heart rate. However this time around it seems as if my heart is beating so fast so frequently that it's hard to catch my breath or just relax. It's also happening during the night when I'm trying to sleep. Anyone else experiencing this? It feels more than in my past pregnancies. I have been talking to my doctor about this and she said it's anxiety but I really don't feel that it is. I'm pretty open about my mental health and concerns with it too and this just doesn't feel like anxiety .

Thoughts?