My continued loss has happened slowly over the last 15 years. But yes it can happen fast, and some do lose a lot over night even. A 10db difference from test to test even in the same day is not unusual. The hearing test I have found to be very subjective, and will change due to you being tired or stressed. And to be honest we are in a very stressful time. I would not worry to much about it yet. You are getting use to the aids, see you just got them in November, and it is normal to notice the differences. I would say keep notes about your hearing and as soon as you can see your Audi, show him the notes, and more than likely you will just need to get a minor adjustment to your aids.
Also, it is very common without your aids on to feel like you have lost more of your hearing, that is because you are getting use to the louder sounds your aids are giving you.
Also, my biggest challenge was as still is with understand speech, I have the speech understanding issue in all of the environments that I go into. I now wear Oticon OPN1 ITE aids and they have been tuned for me by a wonderful Audi over about a 14 month time frame, and about 10 different adjustments to give me the best hearing that I have ever had with or without hearing aids.
Be patient, keep notes, and keep working with your Audi.