How do I lose 1 of my 3 ads?

First of all, am I right in thinking my adsense column in the side bar has disappeared because adsense only allows 3 ads per page?

If so, how do I get rid of the middle ad in the 3 ads on my posts?

I have tried suppressing it but that just moves it down (I think), it certainly doesn't remove it.

Thanks!

 

You need to put adsense on the left, 2 blocks on the left, so the third one will be in the middle.