A deadly glass of juice!

I have this horrid feeling that I will fail my glucose test whenever I have to take it (with Landon, I believe I was around 25-26 weeks). I had a glass of 100% no sugar added juice, and I feel as though my heart is racing. Its as if I overdosed on natural sugars... its 3 hours later and my body STILL hasnt processed it properly. Im so shaky and dizzy, its ridiculous. Sknce the cup of juice I have had a whole grain bagel and several bottles of water. I feel so weird... I think I should bring this up to my dr next time i see him. I do NOT like this feeling....