Panic attacks will make you feel and think you are dying. I know because I had them so bad I became housbound for the most part, and only after I started getting them at home did I seek help. They are very frightening. You know your heart is fine, so this you can relax about. What happens with a panic attack is the same thing that happens if you are in a very serious situation where you feel the need to fight or run. For some reason the brain senses we are in a "fight or flight mode" and rushes adrenaline throughout our bodies to give us the energy to do what we need to do. Since we are not in this mode the adrenaline has nothing to work on and it causes these panic attacks, with the pounding heart, nervousness, sweating, etc. It's a very normal thing coming at the wrong time. The best thing you can do is start doing something physical to give the adrenaline something to work on, and keep talking yourself down by saying "I'm okay, this is a normal response coming at the wrong time, and will pass." I had to go on medication for mine with great success. Try therapy to learn how to cope with this, as I'm sure your very anxious over your tachycadia. Also, pay close attention to your breathing. When we're anxious we tend to breathe more shallow, so breathe slowly in thru your nose, and slowly out of your mouth 8-10 times. Your anxiety will make your heart beat faster, so getting this under control will help immensely. Take care....
The tingly feeling is DEFINITELY from stress, I get this all the time. I, too, also have hypochondriac thoughts. I find that having hypochondria also makes us more in tune with our body. Seriously, if I get an itch I freak out. I think the best thing to do is talk to a close friend or relative. I do this often and then I realize how ridiculous I sound worrying about things. Once you say it out loud and you realize you're going to be okay, it makes the coping easier.