Hello, I was lifting weights last night, I heard a pop in the area where my neck curves upwards into the back of my head on the left. After the pop occurred, I felt dizzy, had a temporary headache and my vision got blurry, about half an hour later I felt really nauseous and vomited. It has happened only twice and have only ever occurred after a particular heavy lifting gym session last week. Can you please tell me what you think the problem is?

Thank you I appreciate it!