Don't worry. You're not alone. *Takes your hand*. Everyone else out there experiences this at some time in their life. Here we go. It's-
You know it. You're scrolling down a page of pictures of your favourite ship, and suddenly BOOM! Your heart starts racing and lava starts partying in your gut. It depends on what your ship is to be able to tell how serious the Feel attack will be. If you ship, say, Lady Arwen and Aragorn, or Superman and Lois Lane, I can assure you that the feels will not be serious. However, if you ship a ship that is (I apologise) a little unlikely to ever happen, (Johnlock, unfortunately) then the feels will tear through your very soul.
Feels are even well documented in history. Not everyone knows that spontaneous combustion is actually caused by excessive feels. There is even a legitimate definition:
“Feels” is a shorthand for the word “feelings” that is used to describe an intense emotional response, such as sadness, excitement or awe. The term is also commonly associated with the phrase “right in the feels,” which indicates that something has deeply affected the speaker.
So the next time your heart starts racing and your blood pressure rockets, remember:
It's not a heart attack; IT'S FEELS.