popping sensations in my head, shaking and tremors.

Hi! I have been expieriencing some very very strange issues related to my head the past 2 years. Ever since September 2009, I have had some very strange situations going on with my head. What happens is that many times throughout the day, I feel popping sensations in my head. I can feel them anywhere, but mainly they seem to be at the back of the head toward the top. I have also had many issues derived from this. I feel shaking and tremors. I feel shaking in my arms at times, my neck, sometimes my head twitches. I also have feelings of fear and extreme anxiety. It's hard for me to turn my head around, and when I do, shortly after I almost always feel a pop in the back of my head. Now I had leaned to deal with this and wasn't overly concerned but then tonight happened. Around 7 hours ago, I was in my bathroom scratching my head all over. I have an extremely itchy scalp. I have shaking sensations when i scratch my head as well. Well anyway, i started to scratch behind my left ear when i felt a pop. I looked into the mirror and after the pop, my pupils started to grow rapidly into a nearly-dilated state. in well-lit room. I didn't change the lighting or anything the pop in my head was followed by a a very brief dilation of my eyes for a few minutes. My mom when I told her about this shined a flashlight into my eyes however, and my eyes were responsive. Now other then a brief few minutes, my eyes have not been dilated sense. However my head has been popping alot. I also still have the slight tremors and my anxeity is at an all-time high. Also my eyes are kinda red my eyes are uncomfortable. They have been for the past few days. I am concerned that I might be expieriencing a possible brain anerseyum. Please give me advice and an opinion about this please? I am 19 years old, don't do drugs other then smoking and is of a good weight.