My zen cart stopped working

My (first) zen cart site had been up for about four months without any problems. Out of the blue yesterday when i went to look at it, it would not load. The admin cp is still fully functional. Oh, and I haven't edited the site in weeks.
The browser says waiting for "www.veteranclothing.com" for 30 seconds or so, finally redirects to https://www.veteranclothing.com/shop/index.php as it should but nothing is displayed on the page. View page source comes up blank too. I checked the index.php page through ftp and it looks ok. I'm guessing the problem is some other file that's being called upon, but not sure.
Hoping someone with more experience can lend me a clue. . .

Talk to your web host. Ask what changes they have made recently on your server. Have they upgraded PHP or MySQL, changed the security settings, quietly moved you to a different server? The length of time that it takes to get a connection to the site suggests that something is very wrong on that server.

The admin still works because it's not in the same place. Look at the URL. It appears that you have one of these arrangements whereby a separate copy of the files is stored elsewhere for SSL purposes and that's where you admin accesses are being re-directed.

Also worth trying the utility mentioned in step 2a of this FAQ: https://www.zen-cart.com/tutorials/index.php?article=82