Hello, welcome to the forum and thanks for your question. Why are you worried about this, if I may ask? Poisoning by carbon monoxide is fairly rare but obviously serious when it happens. The most common symptoms of CO poisoning are: dull headache. weakness. nausea. vomiting. confusion. dizziness. difficulty breathing.
Hello~I don't think you have anything to worry about. You had the door open, so air was getting in, plus, you were only there a few minutes. You have no headache, so that is good as well. I am sure you are fine. :-)