Argh, this is a hard one. When I wanted to have a baby and it wasn't happening, everyone said it is because you are worried about it so stop worrying. And then I'd be worried about being worried! So, I get where you are coming from.
You've had a doctor check out your heart and all appears normal. This is awesome! This should ease your mind but isn't. So, yes, you should start believing that what you are experiencing is related to anxiety and stress. When we have anxiety/stress-- we can hyper focus on our body and feel every twinge, blip, etc. This is probably what is happening.
It would be wise to talk to someone about anxiety and coping mechanisms as that could really help you. good luck
The first thing I'd ask is, do you feel anxious other than this suspected heart symptom? In other words, in your daily life, are you having anxious thoughts and irrational fears that are limiting your life? Or is it all physiological? Let me get a bit definitional here -- your doctor says you have acute chronic anxiety and stress, but you say this isn't normal for you, it's new. If that's true, this isn't chronic, is it? Chronic means it's been going on and keeps going on and doesn't go away. You actually can't actually be acute and chronic at the same time, right? That's why you don't get mental health diagnoses from your regular doc, you get it from a psychologist, who can then determine if you suffer from anxiety or not by talking to you, not by giving you those silly questionnaires. (Can you tell I've taken a few over the years?). Your profile doesn't list your age, but if you're young, it's unlikely to be a heart problem, and a huge number of people use the word palpitations to describe something that isn't palpitations of the heart but something else. Now, if you are a chronically anxious person, worrying about worrying is pretty much the definition of chronic anxiety, but it usually takes a while to get to that point -- you're scared of things you weren't before and that makes you scared you'll be afraid of other things and so it goes until you're avoiding much of your life (welcome to my world). Now, one thing you don't mention is a stress test, which is the only heart test that is worth anything -- it tests you while you exercise so you can determine whether your heart can take the amount of output it should. Most EKGs are pretty worthless except to flag the need for more comprehensive tests. So I'm still wanting to know, are you perpetually anxious and scared or only because of this and only just lately?