Icons showing as grey boxes

Hi, so I just uploaded my site from my localhost and when I uploaded several icons now show as grey boxes (the search icon that should be in the menu, the up chevron that should appear in the back-to-top button that appears when you scroll down, as well as many icons within the Page Builder plugin). I am running my site on Vantage by SiteOrgin. The only solution I could think of is to reinstall the theme. Is this the answer? If so, will deleting the theme and redownloading it ditch all my custom settings and screw up my site?

Thanks for the help, I really appreciate it.

theriochurch.com