Hi, I'm 17 years old, female, 5ft8 and weigh about 9 stone 1lb. My blood pressure is 96/55 which my mum said is low? I walk briskly for 1-1 1/2 hours a day, and do other activity like judo for half an hour on Fridays, and I train for the race for life on Thursdays. I tend to get dizzy and I feel cold a lot, but I drink enough. What do you think?