It's common for your anxiety to spike at night. Your brain is tired from being active all day, and there is less around you to provide a distraction. Those few moments before you fall asleep can mean your mind is kicking into overdrive when it should be getting some rest.
I find I get crazy dreams when I am overly fatigued, sleep deprived, or going through some big changes in my life.
You have to remind yourself that your anxiety is working you over...it's not your heart, it's not a horrible disease...it's your anxiety. You have to talk yourself through this when you start to feel those symptoms coming on.
I've been to the doctor several times and I've had lots of tests done. I was on a halter monitor, I've had EKG, lots and lots of tests. I don't even like going to the doctor because I feel like I'm being a pain in the @$$.
I lately started to have these anxiety attacks, too. It started about 2 weeks ago. It gets really bad when I go to sleep, whith these same sintomes you experienced. It's like I'm having a big discharge of adrenaline, like falling out of a high build or in a roller coaster. It wakes me up several times during the night.
Last week I went to the doctor and when I was there I satarted to get really sick. I stoped to feeling my arms and though I was having an AVC. But, fortunately (or not), it was just consequences of the anxiety in the body. I made a lot of tests and it was nothing concrete, so I guess it's emotional plus the lack of sleeping. I also suspect it could be something like a panic attack, because I have depression in my personal history.
I recomend you to go to doctor and try to breath slowly and recognize the feeling you having when It happen again. And try to exercise, It helps to sleep better.
I'm not a doctor, so It's prudent you don't take me much seriously. It's just a experience sharing.
Ps: Sorry my English, I'm not native speaker.