Guys, whats happening to my SEO?

Its been like 4months since i launched this saas, and i havent advertised it or did any marketing of it so I was ok with impression and click in beginning.

But from like 1 month ago my many page got indexed(30 pages) automatically maybe because of sitemap and started gotting good amount of impression, i was really happy but now i dont know why my 10 pages got deindexed automatically and my impression and clicks dropped so much too from last week, If anyone know whats happening pls help me.

Author: Amrit_Pokhrel