But, airlock activity is not a real indication of fermentation. I have a bucket/lid combo that bubbles slowly for 8-10 days on a good ferment. I have another that bubbles for 2 days and stops abruptly.
If you are really concerned, take a gravity sample and see if there is progress (or krausen for that matter.)
EDIT: I just re-read and saw that you are seeing the yeast getting sexy and the krausen forming. You're golden...chill!
Most importantly, RDWHAHB and let the yeasties do their jobs.