Website gone, can’t log in

Hey there!
I am completely confused and need some help finding the key to whatever happened.

What’s going on: I can’t log in anymore into www.remarpro.com (I now created a new account to use the forum), it also says that there is no account linked to my e-mail (when I try to get a new password). Before that the website (www.againstthelight.org) was not reachable anymore (for me as well as for others) and once a person even said, he was trying to open my website from google but was transferred to a spam site.
My “old” or original username is “Anskar” and I still have the password. But I simply can’t login anymore.

Other (hopefully useful) information:
I use strato as a host (everything is paid), as for now I deactivated the domain from this site.
I used the templete “photography” from envato market (https://themeforest.net/item/photography-responsive-photography-theme/13304399), which is paid as well.

Also I am a complete newbie when it comes to the website, I tried to did the learning by doing thing which actually worked pretty fine. As a lack of internet the past 2 months I did not really do a lot on the website. I was still going to the admin page every now and then to check the stats but I did not upload anything.
The last thing I remember doing was to change the “contact us” e-mail to actually prevent hacking (so I would’ve two different e-mails).

So whats going on? Maybe something completely “stupid” and obvious (which would be great) or did I actually got hacked?

Already a big thanks for any help or advise. I’m quite desperate as I don’t know how to even start finding the problem..

The page I need help with: [log in to see the link]