Yup, vary the distances for both activities.

As well I'm guessing that like a lot of seasonal athletes, you got back on the bike in April or so and may now be burned out. You'd be the 2nd person I've seen comment on felling like they were in a rut.

Maybe take a week off and do maybe 20% of your usual. Go hiking or kayaking. Maine has that in abundance and doing a different activity lets you use your conditioning.

I also discovered years ago that I should do a 5-6 week cycle of gradual building of distance and time, then a back off week. Maybe work that in to your schedule.