Shadow-banned or something by Google?

Hey guys. I used to get a decent amount of traffic from Google. Since a few months or so my Google serps previews went down a lot and so did my organic visitors. The odd thing is: almost all my vistors from search engines now are from Yahoo, Yandex, Baidu, Bing and DuckDuckGo. Only very little from Google, while I used to get the most from Google (obviously, since its the biggest by far). Do you think Google could have ‘shadow banned’ my site or something? And if so, what could be possible comon reasons? Like keyword spamming? Too much affiliate links? Etc. etc. etc.? Thanks!!!