POTS?

I’ve been struggling with what feels like constant anxiety for the past two months, and I’m wondering if anyone else has experienced something similar.
Almost every day I have this overwhelming sense of impending doom that comes in waves. It’s not always tied to anxious thoughts—it often feels like my body decides something is terribly wrong before my mind does. Even when my heart rate is normal and I’m just sitting or lying in bed, I get this intense feeling that I’m about to collapse or die. It’s terrifying.
A lot of this started after a hospitalization where I had a very fast heart rate, low potassium, elevated white blood cells, and elevated lactate. Since then, I’ve had a normal echocardiogram, a 10-day heart monitor that only showed rare PVCs/PACs, and multiple doctors have told me my heart looks healthy. I also have multiple sclerosis, and my cardiologist suspects I may have POTS, so I know there are physical things going on too, which makes it even harder to tell what’s anxiety and what’s not.
Some of my symptoms include:
Constant or recurring sense of impending doom
Morning anxiety that’s often the worst
Feeling like my body is “bracing” all the time
Heavy, shaky, weak feeling
Nausea and occasional vomiting during intense episodes
Feeling detached or “off”
Hyperawareness of every physical sensation
Fear that doctors have missed something serious
I feel like I’ve become trapped in a cycle where every sensation convinces me there’s a medical emergency, even though I’ve been evaluated multiple times. My therapist believes OCD and panic disorder are playing a big role, but the physical sensations feel so real that it’s incredibly difficult not to believe them.
Has anyone else had anxiety or OCD manifest primarily as a persistent feeling that something is catastrophically wrong with your body? Did it eventually improve? What helped you break out of the cycle of constantly believing you were dying?
I’m just looking to know I’m not alone and to hear what actually helped other people.