Take a break. You've had lots of good suggestions.
This is why I don't "train." I just ride. When the voice in my head says, "you are slow," I put in a little more effort, with intervals or longer rides. Most of the time when I am doing this the voice is saying, "I hate this."
The past 2 years I hardly did any rides over 30-35 miles. I still had the same total miles, but I just didn't have the "feeling" to do lots of 50+ mile rides. All of a sudden this year, I am doing longer rides and riding a little more. It just happened...
2015 Trek Silque SSL
Specialized Oura
2011 Guru Praemio
Specialized Oura
2017 Specialized Ariel Sport