Pressure feeling in head.

Hi. I need help with this problem please. I have been told i have ectopic heart beats. Randomly throughout the week i have this feeling below the sternum like a flutter then a little thud for a second or two. then i get this rush feeling to the head. and lo light headed for a second or two. it feels liek pressure in the head for a bit afterwards. I hae had 5 e.c.g's a echo cardiogram and loads of blood tests.Never found anything. they keep saying its ectopicas. so i have a structurally normal headr and the only thing they ever found was slight sinus tachy. should i be worries. this is really frustrating ive had this now for a year, soe days thwere is no problem weeks sometimes then it could happen 2 3 4 times a day or week thanx help would be good.