I'm 21 years old, 170lbs, 6'1, and my left arm is numb and I've been having weird chest pains all week. Heart?

I might be freaking out now, I've been known to be a bit of a nervous wreck so no one takes me seriously often. Right now, my arm's been numb/weakish for about half an hour. I didn't have any chest pains today or now, but I have been for a week now slightly on and off....could be nothing. One day about a week and a half ago my heart sped out out of no where while I was sitting, then went back down. Now I don't really have any other symptoms but a strange arm, but I'm slowly feeling nauseous and shortness of breathe mostly because of anxiety at seems so its hard to tell if anything is wrong with me. I've been contemplating calling 911 for maybe like an hour now but if so I feel like something should have happened by now. Can I have a heart attack at this age? I'm really worried.