I was checked by doctor and he siad i had low blood pressure so how dangerous can it be? I was like 14

Depends on how your body handles it. You could pass out and hit your head or you could be perfectly fine. You are very lucky, high blood pressure is more dangerous, your GP will keep an eye on it. No need to worry If you don't feel any symptoms, you're probably fine, even fortunate. Depending on how your body reacts, if BP got too low, the most likely bad effect would be getting light-headed and possibly fainting from not enough blood (and oxygen) getting to your brain. That would be actually the same as "shock" referred to in first aid possibly from blood loss form bleeding.