I'm not sure about the contents of cloud 9, but if it contains mephedrone
(which is pretty likely), the mephedrone metabolizes into methyl-ephedra, which is similar to ephedra only 3-4 times more potent and is eliminated from the body pretty slowly. I have tried pure mephedrone myself and experienced the same problems of tachychardia and lack of sleep. If you're really scared, calla doctor, but in my experience you just need to relax (don't panic over the heart rate! ephedra is a stimulant and worrying will just make it worse) and drink a lot of water.
Hope this helps!