Sleepie,
I can relate. I was a hot mess still at 6 months. Seriously.
Part of my recovery has been moderate physical activity.
I bet it has helped me.
What you are saying seems like anxiety. Not your heart or resperatory system.
If you can, see a dr. It might ease your pain. Obviously, don't let him give you anti anxiety meds.
Have you tried exercise at all? If you are feeling stressed, try some jumping Jacks or dancing around the house. Do it for 30 seconds, rest for a minute, 30 seconds rest...for 6 minutes. Try to crack a sweat. Get the heart rate up.
It may help relieve some of that anxiety energy.