Your experiencing sweating, tunnel vision, dizziness along with nausea most likely are having coronary insufficiency!!! Take a baby aspirin, with Gatorade or water and immediately call 911. Get to a cool restful place and lie down. Tell someone close by how you are feeling and that you may be having a heart attack and help has been called. If you have Nitroglycerine tab take one. Get help.
OMG!