What Are The Ill Effects Of Smoking Marijuana?

Hi Dr. Grief. I have a weird pressure (can t call it pain) in the back of me head. It gets worse when I m tired or sleepy. I have been smoking marijuana since I was 16, 27 now. But the use has been very regular for the past few years. This pressure is something I noticed about a week ago on a trip with friends. I barely slept for five days and was smoking VERY large amounts of ganja and hash with friends, as well as drinking during those five days. I don t know what the pressure could be, but it gets worse with what we call spike here. I suppose you d call it skunk where you are. I haven t been smoking for a couple of days, but haven t noticed any real change in the pressure. My theory on what it is is that it s a build up of a chemical other than THC. The hash I was smoking was not very good and had something laced in it. I also really feel the pressure after smoking something I know to be inferior, possibly adulterated marijuana. Again, my theory is that some portion of these chemicals tag along with the THC into my brain, or some such. But you are the doctor. Do you have any idea what might be wrong and how I can reduce the pressure in my head?