how much yoga is too much?

I am in Halifax with my mom christmas shopping. I went to Moksha yoga over here and did a 90 minute class today. it was great. Moksha yoga is a bit more sedate than the yoga at Dynamic Fitness but you sweat a lot and feel good afterward. I did yoga this past week 4 times- sunday, tuesday, thursday and today. I swam three times this week and have been finding that the upei swim workouts are getting a bit harder and longer. i ran twice this week on the treadmill and did intervals both times, I am planning on going running in halifax sunday morning. My weight has been staying pretty constant at 152-154 depending on when i weigh myself and what i have been doing beforehand. I am going to get my roadbike set up on the trainer at my place in town in the near future and start doing one or two trainer cycle workouts per week.