What do the numbers 3.9 AHI and 90% - 11.1 mean?

I started using my cpap about 2 months ago. I had really bad apnea (over 30 episodes an hour). Also extremely loud snorer. When I got my cap I was so happy because everyone that I know that has one told me how great they feel after using theirs. I feel miserable! I have a runny nose and a cough that...