Changed themes, and now traffic is gone 2 weeks in!

I can see people reporting this in outside forums, but couldn’t find this in this one.

I’ve not seen this happen before. Changed from ignite to Linten theme. Smooth, easy.

And then all my traffic stopped cold. 95% gone.

I get very little traffic anyway, but darn it, it’s mine!!!!!! I worked hard for it!! Now I switched back to Ignite, with NO understanding of why this would happen. I plan to change some other themes, too (have 5 blogs) but this is unacceptable. If this is the norm nowadays, there should be a big warning on the main theme page.

No, didn’t change anything else. Nothing. I had ranking for just one page, and now it’s all gone. Very frustrating.

Any ideas on why?