Consistent higher HR with lower power at that HR means you're tired, which is a good thing and the signal to put in a couple recovery days and see how that goes. Your schedule is quite ambitious. My approach is to use TrainingPeaks or some other website to keep track of my numbers. Then, since you're not familiar with how training plans work, find an inexpensive 12 week plan and see how that goes.
IME a fairly reliable way to tell your readiness for hard exercise is to take your resting morning HR. After you get up and pee, lie down and watch your HR for a few minutes and record the number where it settles. Usually it will be in quite a narrow range. If it's say 6 beats above that range, you're tired and need some rest or easy days. A much fancier way to do that is to have an HRV app on your phone and record that. I use both.
Another approach is to buy The Time-Crunched Cyclist (book) and use one of the training plans therein. They're structured for 6-8 hours/week, which is pretty common. The book'll help you figure out what's going on, too. Experience is a tough way to get the hang of anything, because experience essentially means learning from your mistakes. Another takeaway from that is "mistakes are good." If you're not making mistakes, you're not learning. IOW, good on you!
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