I'd also highly recommend you get into a Cardio Rehab class, if you aren't already.
They are run by cardiac nurses, you are monitored the entire time you're exercising, and they fully understand the anxiety following any sort of heart event. I have been attending a class since July when I was fortunate enough to avoid a heart attack by having two stents placed. Exercising at home made me very anxious, I was terrified of being alone in case something happened. The class has, literally, been a lifesaver. Most insurance companies will cover the cost if your doctor refers you. Talk to your cardiologist and see if this would be a good option for you.
Peace
Greenlydia
Go back and talk with your cardiologist to determine if this is related in any way. It sounds like anxiety, and anyone would be anxious after a heart attack. But it may be getting the best of you and needs to be addressed. If your doctor says everything is okay, see a psychiatrist and determine what course of treatment is best for you. Make sure he is aware of all your medications and heart attack. I do wish you all the best, and take care.