So the day before yesterday I was inspecting a basic page to see how it was made, I was looking at the head section when I realized there was a label called "style type=text/css" :
I opened it and this what was inside:
It includes a lot of links to many kinds of websites, most of those being adult pages.
This label is included in every page I go, also, I have my Opera account linked with my notebook and my other PC, so it happens on the two devices. A friend of mine who also uses Opera has the same exact problem.
Also, if this helps you, I was looking at the console at some point and it showed me that the AdBlocker blocked a site called "Static Hotjar . com" from redirecting me to another pages.
I wonder if this has a name and if it has a solution, I've already uninstalled and installed Opera again but it didn't work.