porn-update: I found out that when moving to HTTPS I made a mistake in htaccess and my site version without www doesn't redirect properly. You can check the same here:
Redirect Check
You can find in Webmaster Tools Search Console whether there isn't "Submitted urls are not selected as canonical". Google either indexes http version or doesn't even index your page at all!
I have seen slight boost in rankings after implementing HTTPS. Even though it still doesn't work as it should but we have already fixed it. Just my htaccess still behaves like it's cached and it returns to its original state over and over ignoring my redirect changes.