Perhaps you need to set up your commute to be more painless, less stressful. I find the changing clothes, locking up, hauling luggage parts to be tedious at times. I've tried to streamline it with minimal clothing change, keeping spare clothes and shoes at work, taking it easy most mornings to avoid sweating, riding a beater so I don't mind so much if it's exposed to bad weather and risk of theft.

Also, since you're getting a lot of base miles in, maybe it''s ok to ride a bit less on the weekend or change your practise. If you were riding on Saturday and Sunday, cut back to just one day. If you rode once a week, go for long rides every 2nd or 3rd week and just short jaunts the other weeks. Join a club or start to race as a new motivator. Take the bike to some new spot to explore.