What if I know my call is wrong?

[ballgame99]

I had a situation come up the other night that I wasn't sure how to handle. I had called, IMO, 3 quarters of really good ball. Wouldn't change a single call. Then at the start of the 4th quarter, there is a little contact by the defense on a rebound, and when the offensive player went back up the shot clearly got blocked clean. The problem? I blew my whistle and put my fist in the air. Not sure why. Well now what? I go ahead and signal the foul and took a little (emphasize little) chewing from the coach.

Any advice on something like this? I don't plan on making a habit of it, but what, if anything, do you say to the coach in that case? Do you admit you kicked it? Do you call an IW? I couldn't think fast enough to call a phantom travel or something.

Still not sure why I blew my whistle...

Full disclosure, I'm only a second year official so I'm still learning and gaining experience.