Shame about your HbA1c - don't be too hard on yourself though - the cold certainly won't have helped. Maybe a few minor adjustments would help. Try to fit a bit more exercise into your routine? I find my BGs slip when my level of exercise slips. Maybe lower your carbs right down for a couple of months? If you can't do either of those (or they don't work for you), have a chat with your doctor about more or different meds. Make sure you keep a good food diary and, if you are able to, test more frequently for a while - not sure if you're able to get access to test strips?
Sorry, I don't know anything about your circumstances, but they're the things I'd try.
How do we know that? Are you basing it on your A1CNow kits or a proper Doctor's test? If it's the former, then I'm not sure how much I trust them - I've had a few bum results in the past: viewtopic.php?f=1&t=25624&start=15&hilit=a1cnow
What are your regular BG readings like? The difference between a HbA1c of 5.8 and 6.6 is only 1.2mmol/l or so. It could be that your stress levels have put your BG up a little.
If so, then getting stressed, about getting stressed, isn't going to help you much. Concentrate on controlling the things that you can influence, and your BG will take care of itself.