Maybe get your electrolytes tested (your blood levels) - your heart can 'flutter' over an imbalance of any of the following:
How much water do you drink? Maybe since it is a dry climate/less humid here that you might not drink enough water...try drinking more to keep hydrated even if you don't feel thirsty. I would avoid your coffee - that can just worsen your anxiety
, and it's dehydrating too.
It wouldn't hurt to go to a doctor and get checked out - even a simple electrocardiogram or wearing a HOLTER monitor
(a monitor you wear for 24 hours under your clothes, and can press a button when you feel palpitations - then the dr gets a readout from that). That way you can be sure it isn't a heart problem.