Primary fermentation very quick, what should i do?

I started a 5 gallon pumpkin ale on Sunday. I checked on it yesterday and the airlock was bubbling away. Today, all finished. I'm new to brewing but aware that 'primary' fermentation takes about 4-6 days. It's never been this quick (2 days).

Should I be concerned? Should I transfer to the carboy (secondary) now? Or should I wait a few more days.

What would cause this to happen? I'm thinking there may be a leak somewhere. When I was cleaning the bucket with sanitizer, some water seemed to leak (very very minor) between the bucket and lid. I thought maybe it was just excess on the outside of the bucket or maybe the lid wasn't fully snapped on.

Anyways, what should I do? Any and all advice would be greatly appreciated, as I really want this beer to turn out well.

Airlock activity isn't the best indication of completed fermentation. Do you have a hydrometer? After about 7 days of fermentation I would take a reading. A stable reading over a few days will tell you if fermentation is complete.

If you have a leak in the seal of the lid, as fermentation slows the CO2 will go out there and not through the airlock. The water in the airlock provides more resistance for the air.

It may well still be going.

Different temperatures, yeast amount and health, different amount of aeration can all affect fermentation time. Nothing to worry about.

You know it started to ferment, so it has made alcohol. The alcohol will protect the beer. Relax. Move away from the fermenter and don't touch it for about 2 weeks (or longer if you can manage it). Do some reading on the site, there is no issue with leaving the beer on the yeast for a while, and it will actually help the beer.