Your situation is actually really similar to mine. My first panic attack happened about a month and a half ago, and I've had maybe 3 or 4 since then, with most of the symptoms that you mentioned (racing heart, fear of passing out, etc.). I've had increased anxiety, and I don't really feel like myself anymore. I'm seeing a therapist, and I had a full physical and blood tests at the doctor just to make sure everything was okay. You may want to do that, just for your own peace of mind. After the first panic attack, I thought there was something wrong with my heart, but everything checked out fine, and I'm perfectly healthy.
Like you, my panic attacks seem to happen at night when I'm about to fall asleep. My anxiety is always worse at night too, because it's just so much harder to calm yourself down at 2 in the morning, you know? But there's certain things that you can tell yourself. What worked best for me at first was just repeating "I am safe, I am warm, and I have people who care". Saying things like that only worked for a little while though. The thing that actually works, even though it sounds almost crazy, is to accept the situation and just say "Whatever happens, happens," or "Whatever will be, will just be". It's like saying "Yes, I may die, or I may not. The chances of me living are much stronger than the chances of me dying, and letting this anxiety and worry control my thoughts isn't going to do me any good." You never know, different things to say will work for different people. Learning to control your breathing can be very valuable too. Eventually you'll be able to see that this is all psychological, that it's all in your head. :)
I really can't say for sure if you have health anxiety, because I'm obviously not a professional. You may develop health anxiety if you don't go to the doctor to have yourself checked out. It's like catching something early; I probably would have developed health anxiety if I hadn't had those first worries of mine about my heart addressed. I'm not you though, and health anxiety may work in a different ways.