There is not much you can really do about it. It seems to be a common question asked when sellers rank up. I would just try to ignore the rankings/stats and just make sure that you deliver good service for any orders that you do get.
I did a bit of manual research and from what I can see the algorithm tries to allocate a certain quota of unrated/level 1/level 2/top rated/rising talent/pro verified gigs per browser page of gig listings (40 gigs). I guess it is for fairness to try to give a range of different gigs a chance when someone searches for a service rather than defaulting to just the top rated/level 2/pro verified gigs on the first page. It seems to shuffle the gigs around roughly every week which can make it a bit frustrating if you start obsessively checking your stats every day.
You can try choose to promote your gig(s) which might get you a few more clicks even if you have dropped quite a a few pages down. However doing that will cost you a bit of the revenue and you will get charged for clicks even if they are not converted to orders.
If you update you gigs (even minor updates) then you will just end up with your gig disappearing briefly while Fiverr checks that the gig still meets their TOS.