It's supply and demand, in a way. Right now, there's way too much demand (transactions) with little supply (miners with their confirmations). Miners typically choose to include the highest paying transactions, so we have a lot of people bumping up their fees, driving the prices up way higher than normal.
In how many days do you think the fees are back to reasonable (with that I mean, back to what they were a few weeks ago)?
No one can really say. Things are settling down a bit, with the number of unconfirmed transactions going down gradually. I would say maybe a week?