I get nervous for no reason?

I know a lot of people go through the same thing, but I honestly don’t know how to resolve my problems. I’m not sure if it’s anxiety but. Anyway, this random nervousness that I get mostly occurs when I’m on the computer, but it’s gotten to the point where I wake up sometimes feeling perfectly fine, and then I kind of force myself to think about the “anxiety” that makes my heart beat faster and my mind to lose focus. Sometimes it occurs in the shower, at school, when I’m doing my school plates and although a lot of the times I don’t even have to think about it to usher it on, other times I purposely think about it. Also, whenever I begin to feel this nervousness conquer me and I become unable to focus on things and do the things I love, I have this tendency to feel for my heartbeat and I know doing it makes it all worse because I’m kind of paranoid about my heartbeat and heart problems and stuff.