Circumstances change.

Hello all I'm new here, looking for abit of help. I recently had circumstances change in my pip, so I had to tell them. They sent me a form out till fill in & send back. I got a text on the 20th August to say they had received it. Then another text on the 29th to say my pip review had been completed and I'll receive a letter in 2 weeks to tell me the decision. Now in worried because how fast they processed this form & not sure if it's a good thing or not. Has anyone had the same situation? If so what was your outcome?