What Causes Acute Onset Of Dizziness Along With Vomiting?

Question: I am 71, 182 lbs, and take several prescriptions which I have never had trouble with. For about nine years I have been getting sinus colds which used to turn into sore throats and progress. I took something with the main drug in Mucinex (guaifenesin) and now I use Mucinex DM. That seems to clear up the related symptoms of headaches, sore throats, etc. I am concerned because I had a sinus infection (no temperature, however) and was taking it for about seven days. I felt better so I quit taking the Mucinex. A few days later I again started having the symptoms. I took Mucinex and felt better, and I was painting outside. I drag some water, but I perspire a lot and my hair was soaking wet. I was sitting on a stool and painting a table umbrella. I wanted to open the umbrella and lean it against something so it would dry properly. I had what I called one of my "attacks" and became so dizzy that I felt like I would immediately. I sat down on a lawn chair and began drinking water. I consciously breathed deeply for about ten minutes until I felt a little better. I knew that I should go inside and lie down and drink water. I did that. We had plans to go out to dinner with another couple. I brought two bottles of water and a Slimfast along because I had only had yogurt for lunch. I thought perhaps I needed food, and it was an hr to get to our destination. In the car I got sick and threw up the water and Slimfast. I am never car sick. We turned around and came home. My blood pressure after the first episode was 125/66 but my heartbeat measure was 96 which is high. After I returned home from my embarrassing illness, it was 125/67 but my heartbeat count was 95. My husband suggested that I have a pinched nerve because I have had neck and back pains recently. What do you think I should do?