If you're already feeling uncomfortable with your size then I'm not sure anybody here could persuade you any differently. However, I must say, for your height you do not sound "chubby." My ex girlfriend was shorter than you and the same weight and she did not look "chubby", more curvy, actually. And I don't mean that as a euphemism for "chubby" - I got warned about that plenty by her. But she always used to worry herself silly about her weight as well and still does, and I always used to tell her it was unnecessary.
But as they say, beauty is in the eyes of the beholder.
If you, like her are dissatisfied with how you look then maybe you should go back to the gym to make yourself feel better and shed the weight that's giving you worries, but know that from you've said it doesn't sound as if there's any need to be dissatisfied with yourself.