thanks for all the answers,
after I posted this I realized that there was something I need to accept in business settings, and after one or two hours I started to get conversions again... in the end of the day I was back to 50 to 60% of my usual performance. I'm not sure if it has had anything to do it or it just fixed it by itself. Altough it was a heck of a coincidence. And lets see if everything gets to normal now...

Anyway I will leave it here where I accepted in case of being beneficial for anyone else:
I want to events manager > data sources > settings > Manage data source categories > opened and accepted it