Rapid Heartbeat

Okay, so, I was attempting WILD for the first time last night and everything was going well (I was resisting all urges, not swallowing, ect) At the 20 minuet mark or so, my heartbeat started rapidly increasing and my eyes started uncontrollably...spiraling, so to speak. I immediately opened my eyes and sat up. It took about a minute for my heart to slow down, but after that i was fine. Anyone else experiencing these problems?