What Could Cause Dizziness After Receiving Neck Adjustment?

I was in a minor car accident almost two months ago, and I began seeing a chiropractor for my lower back pain. An MRI showed a bulged disc, etc., but nothing too serious. I had some mild neck pain as well. I was getting lower back adjustments and neck adjustments at the chiropractor. Three weeks ago, shortly after receiving one such neck adjustment, I began experiencing a somewhat dizzy, foggy, space-y feeling in my head that comes and goes at random every few minutes. Sometimes I have tension headaches in my forehead area and around my temples, kind of like a band squeezing around my head, but I also had sudden stabbing pains in random parts of my head; this would mostly occur as I was lying down, dozing off. This happened more in the first few days of this. When I have a particularly repetitive episode of this dizzy feeling, I sometimes have a slight carsick-y feeling of nausea. I also have a sort of weightless feeling in my left leg when I feel the spacey feeling come on. My chiro is referring me to get a brain and neck MRI to check for some nerve or disc issue. My initial fear was that I was having a stroke! My chiro did a check of my neurological facilities and found no issues, so my more rational guess is that the neck adjustment caused one of the vertebrae to impinge on a nerve. It is not as bad now as in the first couple of days, but it seems to have plateau ed since the first week -- not getting worse, but not really getting any better either. Any thoughts?