TIA's, Small Strokes, memory, cognative, What?

I am experiencing various problems mostly with memory.

History:
I am 49 and was diagnosed a year ago with diabetes. My A1C was 6.5. I was very tired. I could fall asleep at the drop of a hat. All I had to do is sit down and start to relax. My brain was not working so well either. My memory was becoming almost a thing of the past. I was having what I call random access bad sectors. It would strike randomly and I never knew if I would recover what I just forgot. I also did not always know I was experiencing a random bad sector. Then I was diagnosed with diabetes. I was going to school at the time and the first indication was, I went from getting A’s and B’s to getting C’s and D’s. Very disconcerting for a 3.56 gpa career. I had not changed how I study. I thought I had burn out. By January 2007 I was also rather confused at times. People would speak and I would hear bla, bla, bla, bla. I would talk and forget what I was saying, even what the subject was. People would call and I would forget they called and I would forget the contents of conversations. Somewhere in there I also experience weakness on my left side for about 2 months.

As my blood sugar regulated this all got better for the most part. I was still experiencing random bad sectors. Though now they were not quite so bad nor quite so often. Within a few months of starting NPH the random bad sectors calmed down to be what some would call senior moments though I am 49 and mine are worse than my 79 yr old mothers. By this time I was not falling asleep so easily anymore either and my A1C’s were down to 5.6.

Meds:
I have high cholesterol and take lipitor 10mg. I have low blood pressure 100/60 but I take 2.5mg of lisinopril for stage 1 kidney failure. I am on Humulin NPH x 2 a day. 7 units in the am and 4 -5 units at night. Also Advar x2 a day.

My memory has never fully recovered. This all happened very fast, I was seemingly Ok in September 06 and by Dec 06 I was not. I had always thought it was high blood sugar related, however last week I had two days of real bad random bad sectors and my blood sugars were low 81 -130, I was not sick. But man I was dingy and I knew it. I was afraid to drive. I was confused, had trouble finding words, sometimes understanding, it seemed at times I was looking and moving through a fog. A dimness? Early the first day my legs were a little wobbly. I was dingy and I knew it.

Now I am back to, hmm, more normal, though I am still having trouble finding words at times, it is random when it strikes. And my memory is messed up. I can’t always remember what I know I know. I call all this random short circuiting. Since the episode last week this is occurring frequently during the day.

What could be the cause of all of this?