I Am Noticing Consecutive And Multiple Irregular Heartbeats. Am I Worried ?

I am seventeen years old and a male. i am 5 foot 8 and weigh close to 160 pounds. I lift weights everyday (bicep curls, romanian dead lifts, bench press, squats, and tricep extensions) and run occasionally. I consider myself to be fit. Yesterday I began noticing irregular heartbeats. This is what happens. It beats fine for about fifteen times. Then it feels like it skips half of a beat. It feels like my heart hiccups. It is a short pause, followed by a beat. This happens consecutively for about 3 times then begins to beat normally for about 15 more beats. Then this process repeats. Can anyone tell me whats going on? Should I be worried? Thank you. Also, i am russian, if that is of any importance. I have been feeling very tired after school lately. I just feel like napping a lot lately. i have also been feeling headaches immediately after school everyday.