Sites gone mad!

Since updating (although it might not be connected) something quiet odd has happened to may home page: https://www.c3tactical.co.uk

Please help me restore to how it should be, the large gaps and content spread all over the place just happened for no reason, I just editing some text and an image, previewed the page and it was all wrong and weird.

I can’t see anything in the code to indicate this issue. I can send the page code but its super long so not sure you’d want it posted here.

Look forward to the answer