I am an 18 year old female- I am 95-100 pounds, 5Ft 2In. My Blood pressure is about 94/56 and my my heart rate is about 86bpm. Recently I have been becoming dizzy/lightheaded, and not just when I get up or sit down, sometimes after I walk for a minute or so (sometimes just when I cross the room) Yesterday I nearly Blacked out when I got out of the shower. My ears where ringing (so loud that I was wincing just at that,) and everything went black, except for the tunnel around whatever I looked directly at. I felt like I was about to start sobbing (really hard) and I didn't know why. Then as my vision started to clear, I saw little grey and purple blobs over everything I looked at, and I began to feel really (really) naseous, and I had to sit down(so I wouldn't fall.) Afer maybe 5 minutes my vision cleared the rest of the way, as did my hearing, and I could get up without feeling like I was going to throw up my entire stomache. Thats the first time anything that serious has ever happened, but I do always get dizzy and lightheaded, (I have also felt really weak for about a month or so) I know this is long and confusing, but I am concerned. HELP!
Since this is not a "Normal" condition for you, you might want to check in with your family doctor as mentioned just to make sure.
As for the nearly blacking out after getting out of the shower, you might have driven most of your blood supply to the surface of your skin. This is the bodyís way of trying to regulate your core temp. Try lowering the water temp slightly the next time in the shower and see if that helps. Also a warm shower and or bath tend to "Relax" the body which might cause your dizzy condition. Finally, drink some clear non-caffeine fluids before showering as you might have been slightly dehydrated, especially if this is immediately after waking in the morning.
PS: I am not a doc but a lot of this info was told to me by one.
I am not a doctor, but, my DD has been having problems simular to you. At this point her doctors feel that her hormones are running wild and she gets dehidrated ez, try increasing your salt and fluid intake, it helps your body to keep the blood volume up. If you still have a problem in a week I would check with your doctor to make sure there isnt anything else going on.
By the way my DD is 5'5.2" and 110lbs with bp and pulse like yours.