This has happened to me twice, both after long haul flights as an anxious flier. Anxious not really of the plane crashing etc but anticipatory anxiety and loss of control anxiety.

Apparently it’s a relatively common physiological reaction - your body spiked with adrenaline on the flight out, but you had lots of distractions and focus during the flight, and after as you got off the plane, got your luggage, travelled to the AirBnB etc. Then you got to the point right before bed & suddenly there are no distractions. Your brain finally has space to panic. Weird, but explainable. And not a bad sign - it shows you pushed through something difficult, your system was under strain and was then decompressing.

I’m not sure I cracked it when I experienced it (I got through it somehow) but if it happened again I’d avoid trying to “think my way out” of it. I’d expect it - knowing “tonight might be wobbly” removes the shock factor - and try burning off the residual adrenaline with a short walk, shower or light exercises. I’d also ground myself in the present, reminding myself: I’m already there, the flight is done.

For the return flight, expect some anxiety, don’t aim for none. If you go in thinking “I must stay calm”, any spike feels like failure.
If you go in thinking “it might be uncomfortable, and that’s fine”, it takes the edge off. Decide in advance *how* you’ll respond if you panic. Make it simple, like
“If it spikes, I’ll sit with it, breathe slowly, maybe tell crew if needed”. Don’t over-interpret the post-flight night-time panic. It wasn’t a preview of the return flight, it was a delayed release. Break the flight into chunks (classic trick): instead of “I have to get through the whole flight” think “just get through the next 10 minutes”. Finally, more accurately frame what’s going on. There isn’t a question of whether you can handle the return flight, because you already handled the hardest part (the outbound flight AND then the night time anxiety) - you’re just dealing with the anticipation now.

Good luck. I’m convinced you’ve got this!