CTR and your cost per click really have no relation. You may just be going through a bad patch of clicks which will pass or maybe you did some bad advertising or something else which google doesnt like and you have been smart priced (meaning google has considers your traffic low quality and have made your clicks pay less).

That certainly is a possibility.

My CPC very lately have decreased too but nothing as bad as yours.

Maybe advertisers are bidding less per click? There are many possibilities...

if your CTR for your site goes up then there a good chance that you will recieve higher paying clicks

why?

because if your getting a better CTR on your site than all your competitors (or just higher in general) then the advertisers would rather ads be shown on your site because they will be spending less money to get more clicks

thats why its everyones insentive to get the highest click through rate possible (within reason of course)

if you were paying for ads in google and you had a choice between putting your ad on a site which had 25% click through rates

or a site that had 2% click through rates which one would you choose?

kind of obvious isnt it?

but with your situation, i would just be a bit patient and things will sort themselves out soon enough

hope this helps

paul