The return on mining is going down 40% in a few days, and will continue to go down.
Why do you say that? What happens (happened?) in a few days?
The
difficulty will be updated.
In a nutshell, the Bitcoin network tries to keep block generation at an average of 6 blocks per hour which is 2016 blocks per 14 days. If 2016 blocks were generated in less time than that the difficulty is increased proportionally.
Edit: I noticed in another of your posts that you already know all this, so your question was a bit odd.