I would like to publicly thank Netmeg and martinibuster for their great advice!
So basically I took another look at the ad units and noticed that the ad unit that went down was a square 336 by 280, the other one that stayed the same was a smaller square 300 by 250. I decided to experiment by switching the 336 by 280 to 300 by 250 and it did go up quite a bit (not quite up to what it was before but much better then it was.)
Now that I'm aware what a difference the different sizes can make, I am thinking that I should have those two sizes somewhere else on my site, in spots that don't perform as well (by me it's the post pages)and keep a constant eye on them, and as soon as I see that one is doing better than the other to then switch my hot spot ad to that size.
Question: Do you find that one size square performs better then the other?
If you allow text ads and image ads is there a way to check how each one performs separately?