I get tingling limbs, loss of sensation, short of breath, temporary loss of vision, headspins and I'm an 18 year old female. I can be sitting for maybe 10 minutes, I move my legs a little and it seizes up with tingling- to the point of pain trying to move it. It happens usually in my left leg, and my foot will go cold. It happens to my left arm occasionally. Today I noticed both my hands had greyish/blue-ish finger nails. In the mornings, (not every morning) I will get up from bed and my vision will completely black out. My head will become very light and my heart kind of flip-flops a bit. My vision and head return to normal within about 5 seconds. It doesn't just happen in the mornings, it happens whenever I've been reclined or even just sitting. I have even passed out temporarily once. The smoke alarm was set off by my toaster because I forgot about it, so I got up from being seated, walked underneath it to turn it off and my vision blacked out, I got short of breath, my heart flip-flopped, I felt overwhelmed by the noise and everything going on and I fell to the ground. I also get sharp pain in the left side of my chest sometimes... it happens enough for me to say it's normal and nothing out of the ordinary. I went through a short period of biting the insides of my mouth in my sleep and clenching my jaw making my teeth sore too- but that's stopped. I'm a bit concerned as to what's going on.