Brewing first beer from extract kit. Its a wheat ale. Used Wyeast wheat smack pack. Added a half gallon of filtered water after boil to reach OG target. Put in basement and its temp was 68* F. Anyway it fermented like crazy the first couple days even overflowing out of the airlock. It has now been 7 days and I thought fermentation would be slow by now but it's still going at a good pace, like a bubble every 5 seconds. After the first 3 days the temp dropped to 66*. Im now wondering if maybe there is a gusher infection or something. Any ideas on why it would still be so active?