A333 : Athough I'm not qualified to give you any medical advice, I would say don't worry too much ! I used to have low bp as a teenager and I remember feeling kind of dizzy when standing up or after bending my body and then standing straight . I was doing a lot of sports, eating healthy food, I'm now in my late 30's and I have a perfect blood pressure . But again if you start stressing about just seek a medsport or medav advice, maybe changing you diet could help !
cheers,
dj