Hi
You're describing exactly what I experience and it's what finally pushed me into going to see the doctor because for me, it's the worst symptom. I visualise it as a massive adrenalin rush into my belly. I get them at night as well and it wakes me up. One of the 3 doctors I saw (I got pushed around from one to another) suggested anti - depressants and talk therapy for my 'panic attacks'. I couldn't seem to make her understand it was a physical thing, not emotion-led. It starts in the stomach, not in the head. I tried to explain what it's like by asking if she'd ever lost a child in a crowd or had a very near miss in the car when you experience that terrible feeling of dread and your stomach contracts and heaves and then after that, the emotions and panic come in. That's what it feels like for me.
As for how I cope, I've had enough daytime ones now to be able to stay calm and wait for it to pass, knowing it will pass. But I find it so terrifying at night (as I said they wake me up and I am convinced something terrible has happened or is about to happen) that I've fought for and got HRT now. This is my first week. I've had one daytime 'attack' in the past 4 days and one at night. It's a great improvement on the past few weeks. It may be a coincidence with starting the HRT but maybe the HRT ia already helping - I'm not sure.
I'm too much of a newbie to suggest a way forward for you but going to the doc (eventually) got me the medication I believe will help and if it doesn't I plan to keep going back until it's sorted. Best wishes to you x