I had 1720 calories today. Too much?

This depends on a lot of factors - like your current age, weight, height, are you trying to lose weight, gain weight, build muscle, etc.?

For an adult male, just sitting on the couch and doing nothing will burn about 2000 calories a day. If you eat less than that, you'll lose weight. If you eat more than that, you'll gain weight.

If you do more than just sit on the couch, your body will use more calories. If you keep your caloric intake constant, again, you'll lose weight.

A 90 minute workout is quite strenuous, and can burn anywhere from 900 to 1500 calories depending on the actual activities you did.

Overall, I'd say 1720 calories probably isn't enough - but again it really depends on a bunch of other factors you didn't tell us. If you are trying to work towards a specific health goal (lose weight, become stronger, etc.) I would highly advise you to talk with a nutritionist or your coach to help develop a healthy and sustainable diet and routine.

It would help if you posted your age and weight too. But regardless, 1720 probably wasn't too many calories unless you're on a strict diet

If you are on a diet, then no. This is the perfect amount of calories for your activity level. If you are not dieting, then you need closer to 2120 calories.