Thanks for all your thoughts. I guess this isn't too common.
Another word that describes this feeling is toxic. It is a lethargic, heavy feeling where I can sense this running through my veins. Like if you've ever had a blood transfusion, you can feel the blood running through your veins. It's very strange and hard to explain!
My blood sugars are fine, I don't have diabetes, I'm not on antidepressants, and it's not a metalic taste either. The metalic description maybe is more of what it makes me think of, metalic, toxic and chemical-like.
I do wonder about what frogprincess mentioned, it being some sort of over dose on minerals or iron issues or something. But I don't know. I will have all that checked next visit. The only thing is that I'm thinking it would probably only show up right when it's happening, since when it goes away it's completely gone and I feel normal afterwards. But something is obvisouly going on during that 30 minutes, and I just hope it's not dangerous and I'm not damaging any organs when this happens.
I'll keep researching....thanks again.