Thank you 
That is also my experience - first threshold interval feels like the last one, one week before. Short power workouts are ok, and feel like before - but my favourite, and my forte, threshold work is completly not doable inside. And also clients returned to the agency so the work will be very intense for next three months. And I am sitting here afraid that I will return to the starting point and my FTP will be 200W I am honestly missing structure and “precision” of the indoor training. Doing threshold outside and seeing that my power goes into high-tempo, SS, FTP, FRC/FTP angers me in a strange way 
I hope that your insomnia will give up and you will return to normal feeling and workouts.