Are my eating habits healthy?

I never count calories but I don't eat much. I'll consume on an average day- an orange, yogurt and a pepsi (while working) the rest of the day I drink water and take long walks and practice yoga. Most of the time I try to make a healthy choice when I do eat something but mostly when I'm working I'll have a bagle, soda, coffee or donut. My days are never the same and calorie consumption is very low. I'm 5'3 and 120lbs (on a good day)