Virus in my PHP files. HELP?

Hello,

Here’s my website https://www.dhyaniyoga.com. I discovered the below problem because my site redirects from FB somewhere else.

I was told by AN hosting that there is “Base 64 D Code” in all of my PHP files. Does anyone know about this? Any tips? I am simply a yoga teacher, but launched the darn thing, I bet I can fix it if I have instructions.

Thank You!
Tara