Permalinks broken

Hello,
I was playing around with my WordPress theme, and suddenly all the permalinks have been changed!

http://www.tanya-n.com/blog no longer works (this was created as a Page), and every blog post (e.g. http://www.tanya-n.com/?p=1124) redirects to http://www.tanya-n.com/slider/japanese-maid

I have no idea how this happened, or how to rectify it, but currently every direct link to a blog post somehow redirects to a page that I have not edited since 2013.

Please help!

Thanks,
Tanya