One of the issues faced by most GAD (General Anxiety Disiorder) sufferers is the out-of-control racing heart, which leads one to hide away from public gatherings and friends-in isolation.
This tends to manifest out of nowhere: the heartrate is a bit fast, and when you employ fear of the rapid heartrate? It increases! That's why it's some times reffered to as the 'fear of fear' You might even think you are going mad.
The good news, however, is that you can overcome this problem. One of the main causes of palpitations are depression and fear, therefore try and avoid being all alone for long periods of time. You can also use anti-phsychotic drugs as they work to relax your mind.
Although confronting your fear head-on is the best solution, most would rather not.
Counselling is an obvious solution, but it's never guaranteed if you always dwell on the past. If the palpitations are getting 'out of control' you can even employ the use of Propranolol Hydrochloride.
This beta channel blocker drug reduces the heart's rate of pumping and thus no more palpitations for some time. But always follow instructions and be careful.
Otherwise, you shouldn't give up. I know how scary panic attacks can be, since I've experienced them several times. Just know that you're not alone. Thanks and always try to avoid unneccessary stress.