From what I understand the impressions is the number of people who see your gig on the page of search results.
Fiverr probably sorts the gigs differently using an algorithm to keep things changing and different. Nobody knows the algorithm or the secret to “beat” the system. A great looking gig might get higher clicks but it probably won’t make a difference to the impressions as they are beyond your control.
Impressions go up and down. Last week I was getting around 10000 impressions a day but just a couple of days back I barely got only 1000. That’s fine. What is most important is the orders you get and the services you provide.