Resting heart rate feels faster/stronger lately

I've been having some health anxiety the last few months about some GI stuff, and lately I've noticed that I can feel my heart pounding faster/harder when just relaxing and doing nothing sometimes -- enough that I notice it, and it's a little alarming.

Is it possible that it's being caused by me worrying about stuff? It's odd that my heart is doing this even when I'm relaxed and not really thinking about anything.