Maybe Google was testing your new domain, typically when you do a change of domain search traffic drops. At least according to my experience and others I have observed. After a while it picks back up and slow climbs to the previous level and sometimes surpasses it.I changed domain and after two weeks the site tripled traffic for two weeks, now it's back to the initial levels of the old domain, what does this mean?
hint, key problem here is "5000 pages" .now, it's gotten worse, we went from 50,000 impressions to 2,500 per day
there are many fewer pages but the position of those that remain is stable, it has not worsened, but out of 5000 pages those that bring traffic are only 600