For four days, my heart rate is rising far quicker and easier than it ever used to. 

I'll walk home and it'll be up at 140 bpm instead of my usual of 120. I can be sitting doing nothing or just stand up and it'll spike up to 120-140 rapidly and then come back down quickly a few minutes later.

I have a history of heart problems in my family so I'm really worried (read terrified) that I'm going to die any day now and I'm only 25. My chest has been aching and it's hard to breathe but that could just be my anxiety. 

The more I panic, the worse I make it but I can't stop panicking that somethings wrong and that I'm going to die. How am I supposed to know what's anxiety and what's a real issue? I don't know what I'm posting, I don't expect much, I just needed to tell someone.