Some changes to a page can disrupt rankings, particularly if they disrupt page content or nav structure. If they're sufficiently large, it may take Google a while to recompute and re-assess rankings, and this is to be expected. At this point, though, since you're not sure what's going on, I would avoid further changes for a while.
perhaps redo the changes you made?
Give it some time. The last thing you want to do, IMO, is to fiddle with a page in a way that might suggest you're trying to test out the algorithm. If the changes weren't manipulative, but Google is needing time to evaluate them, changing again may only confuse Google further.
Normally Google is OK with site changes, but obviously some changes could disrupt your rankings, and some could improve them. If the changes look spammy for some reason, though, Google may well interpret frequent further changes as a confirmation of spammy intent. A site that was marginal might get extra scrutiny. Here, the links together with the onpage changes might be complicating the issue or raising a flag.
Note that I have no idea what the changes were and am only guessing at worst case scenario in suggesting caution. Some years back we had a discussion here about a Google patent that might apply. While there's no certainty that the patent is being used, site histories that I've seen suggest that it is in use. See discussion at...
Google's Rank Modifying Patent for Spam Detection Aug 18, 2012 https://www.webmasterworld.com/google/4486158.htm [webmasterworld.com]
I need to emphasize that most site changes are not seen as spammy... so I wouldn't panic, but, again, I would be careful about reverting back.
