Permilinks messing with blog scructure

I have made the permilinks a custom structure to put links into categories. so my links look like

/%category%/%postname%/

and then I had to set the category base as
blog
because some of the categories were messing with real pages.

It was working fine for months, but I guess I never noticed, I cant click the “older posts” on the main blog page, it is trying to go to
site.com/blog/page/2
and then it says page not found, I guess it is trying to go to the category /blog/ but it doesnt exist?

I am not sure, but messing with permilinks should update all the other links?
if I am in a category, going to older entries works fine.

how can I fix this hopefully without changing permilinks

[Moderator Note: No bumping. If it’s that urgent, consider hiring someone.]