Type 1 Sudden increase in Blood Glucose when I caught a cold

I was recently diagnosed with Type 1 in early August, fortunately for me at the start of September my Pancreas started to work at a reasonable amount of efficiency which meant I am not taking any Humalog at the moment and only 4 units of Lantus daily, however I caught a cold and my blood glucose went from an average of probably 6 to about 8 - 10 however I'm not sure if I can directly link this to the cold or perhaps my Pancreas "honeymoon" period is over. Right now I'm unsure what to do, I was unsure if a Cold would really increase my blood glucose that substantially or if my Pancreas my no longer functional, however I'm still eating without no Humalog and the highest blood glucose reading I have got was 12.4. I was wondering what the best thing at the moment to do was, perhaps wait until the cold passes and then see if my Blood glucose goes back down?

Thanks, I suppose I'll like start taking some Humalog again at very least until the cold passes, thanks