can't load plugin page or menu page

I tried to update my menu page by adding a page, but it didn’t seem to load no matter what I did. I then tried to update a plugin on my plugin page and then I couldn’t get the Plugin page to load.
I’ve read the best thing to do is to deactivate the plugins to solve problems like this…but how do I do that when my plugin page (and menu page) won’t even load at this point?
My site is https://www.testing.adirondackcandle.com

Thanks
Lane Pelletier