I uploaded my headshots on backstage and for some reason they show up sideways even though they are save on my computer right side up. How can I turn them on backstage or make sure they upload the right way?

I would try to open them in an image editor (NOT your computer's default image preview) and make sure they show up correctly. If not, rotate them and save them as copies in a different folder.

They are turned correctly and everywhere else they show up correctly when I upload them.

Have you tried Backstage's FAQs: http://411faq.backstage.com/photoheadshot_help/?