Adsense, 27 clicks = $0.75 how is that possible?

So yesterday I made $40 with a total of 28 clicks with AdSense, today I have 27 clicks and only made $0.75

how is this possible ?

Each click pays a different amount depending on how much the advertiser is paying.

I was wondering because I changed my theme and the placements of my ads, I thought that might have something to do with that, i guess not hu ?

Which ads display depend on the content of your page and how much the advertisers are prepared to pay.

Whether someone clicks on an ad or not might depend on ad placement and your theme.

does ad placement really matters?

Yes, it will affect how many people see the ad and therefore how many click on it. Basically the closer the ad is to the top left of the page the more clicks it is likely to get.

Ok thanks. I guest I need to rearrange my ads…

Put picture ads or text ads on the top left?