Help! Upgrading WordPress broke my site…

I upgraded my website to wordpress 3.4 and it’s caused an enormous amount of damage to my site. Half of my posts weren’t accessible on the site and 404d, and pages 3 and 4 of my posts on my website 404d as well.

I backed up before upgrading (thank god I had a gut feeling there’d be headaches) using PressBackup. After restoring, I managed to finally be able see my other posts that were missing before, but there’s a still a problem. Pages 3 and 4 still don’t work ie https://www.winvenue.com/page/3/. Interestingly all the posts that disappeared were from page 3 and page 4.

I’m not sure why I got all these issues, and it’s really annoying because this is an active website will hundreds of readers. I’d really like the get this fixed, any help is really appreciated. Thanks