Hi. In short..yes, if your level spikes, if it's pretty high quite quickly...it's more common in those who have had no treatment yet (ie. just diagnosed) and have not altered diet. As is dry mouth, headaches, lethargy.
BUT...a] it could easily be caused by a rang of other unrelated issues..and a number of people who are on meds do from time to time feel a bit light headed, etc etc...
AND (more importantly), I would say that rather than asking does diabetes cause this (ie. high or low blood sugar), the question is really what is raising by blood sugar to this extent (and so..what can I do to keep levels down?) In my little opinion, while diabetes Type 2 may well have been causing such problems...it may be your diet which is a big contributor. I now only feel like that if I eat too many carbs (and I don't mean sugars..I mean simple carbohydrates like bread, cereal, spuds, pasta etc)). So, I'd suggest that if you were eating less of them and maintaining a healthy fluid intake - maybe you'd feel a bit better (whether you are diabetic or not). Good luck.