Meridia is still out there.

I checked the timeline of events Meridia collapsed into the black hole. Then The Gloom arrived. So I hypotheis that The Gloom either IS Meridia or that Meridia was moved spacetime fuckery. After all, The Gloom is too big to be from a single or several normal termanid planets.

On another path. Meridia is the onlybplanet we can still visit. Even if currently only to look at the growing wormhole. Maybe they kept it visitable so they could just move it later.

It would explain thr orbital wobble, if a planet suddenly appered where it wasn't before that would cause all sort of trouble. And it would give the bugs a homeplanet for us to purge, I mean liberate.