Having a colonoscopy will NOT worsen cold symptoms. One has nothing to do with the other. It sounds like her cold is just running it's course. It may have even helped her a bit, because of all the fluids she had to take in before her procedure. Just give her a few days, once her cold is gone, she'll probably forget about the whole thing!!
Yes it won't bother you I have had it done many times and I have had a cold with some of them.
Do you mean colonoscopy or colonic irrigation? Colonoscopy would have had no effect on her cold whatsoever. Colonic irrigation might have the effect of worsening a cold, but that is a good thing because it is toxins being released.
No you didn't tell her wrong one has nothing to do with the other. As long as it is a colonoscopy that was done. She may just be moody because it isn't a fun test and she is sick. She may have picked up a cold from another patient that could have been sick at the Doctors office. Buy some flowers and make some soup for her :)