Unless you're feeling overly tired, I wouldn't worry about it. You've made some nice gains this year, so a slight regression at this stage isn't a deal breaker. As rmur said, it happens to us all at some point.
If you're still in a rut and not progressing in a couple of months then it may be worth a looksie at that wednesday training session. I'm a bit of a hardcase-nutjob when it comes to training but even I don't relish the thought of that unholy trifecta you have on Tuesday, Wednesday and Thursday. Maybe swap out those 3x"chewing handlebar" intervals for something else just to change it up a little, like a 2x30 done at a pace you'd find hard but not overly challenging if done for an hour straight.
Personally, I find that if I do too many intervals during the week (no more than two sessions for me please) I start to subconciously back off a little during the efforts which kinda defeats the purpose. If you're a little stale then you may be physically capable of upping the power but mentally just watching the numbers on the PT is all you want to do.
In order to give me other things to think about and stay a little more mentally fresh, I often use the less intense efforts to work on position, like riding on the drops and holding good form, which inturn allows me to become more comfortable and more efficient on the bike. It shifts the focus of the session from being another 'numbers watching' ride whilst still being a useful aerobic workout.
That said, with my gut right now, the only way I could get on the drops whilst on the trainer is if I hung the bars from the ceiling. :eek: