Why Ranking is fluctuation more n more? I noticed before some days there are many more fluctuation in ranking of my healthcare website.

Yes, the same situation happened to me, and known at twitter.com/JohnM/status/776697590943510528 that engineers and algorithms work hard on daily basis.

As I know that there was a new Google algorithm called "Fred" implementing from March 2017 till now. I don't know how many percents websites was affected but it's maybe over 60% sites worldwide. IMO