Suddenly my website layout has changed to a different design! The layout I had all along was a different one and out of the blue, it has changed to a different design. I mucked around a bit but could not find any setting or option that refers to changing the website design layout from one to the other. The one I had/ need, is one that has the "Back to the top" button at the bottom of any user profile page you visit. This new design does not have that button. That is not all, but it is the best differentiating marker to point out.

I also fiddled around and found that, if I go to Settings, that page opens up in the layout design that I had before and if I bring up my profile or any other sub from that screen, then the old design layout stays. But as soon as I click on some post from a sub, it opens in the different layout design.

Can somebody please help understand and rectify this?

Note: This issue is on the website accessed from the laptop, not the mobile phone.

Thanks!