is this a Panic Attack ??

Im not sure if im having panic attacks but lately i would be sitting down and all of a sudden my heart starts racing and id think something is wrong and have short breath and id kinda freak out thinking something is wrong and it would go away and come back . i would feel fine and it would come out of nowhwere . and i think something is wrong its like a peak that comes and goes and couple days ago i woke up to my heart racing and scared me . not sure whats going on .. never had this problem until couple months ago but now that i think about it . it happens more . im only 21