Since yesteday evening the pulse on either side of my neck has become visible. If i look in the mirror i can see my skin move up and down in time with the pulse, and when i touch my neck i can easily feel how hard the pulse is beating there. Normally i don't feel or see anything at all which really has me freaked out. It terrifies me that it could be a sign of heart issues or a blood clot. What could be going on here??