Website and admin back end both down [URGENT!]

Yikes! My website is down, and I can’t get into the back end either. I read through the forums and could only find that answers could be that there’s too much traffic (really not likely), or that I messed up something in the back end… which I didn’t to my knowledge.

The site is https://www.getthatyoumatter.com

My last edit to the site was on Friday, and up through yesterday it was still working fine. This morning I found that it was not registering, and I also couldn’t/can’t get into the administrative back end.

I was passed on this website and I’m not familiar with its setup, but I know that I didn’t change anything drastic. I think that I upgraded the plugins on Wednesday or Thursday.
I am not sure which version I am using ?? Sorry, I wish that I could login to look, but I’m not sure.

Help!