Google Adsense messed up my site. Please help!

Alright so I have the Google Adsense plugin so that I can easily manage my ads on my site. Today I changed themes and went to edit the ads and when I went to save the placement it said that it couldn’t be saved. That it could possibly be a plugin or theme that was incompatible. I tried switching the theme back and it did the same thing. I don’t know if it was because some code got removed or something. But then I tried delete the Adsense plugin and then re download it. When I did that it messed up even more and when I got to verify my account for the web masters it says “oops there’s a problem. Please try again”. And the manage ads button no longer pops up. Also, when I do this and try visiting my website it says I don’t have access. But if I delete my history and everything from my computer I can view it. I have tried changing themes, messing with web masters, and so much. I have no idea what is going on. Is there a code I need to readd to my site since I changed themes? Or what?