Any body is a summer body! Did you want to lose weight or need to lose weight when you went to the gym?
If it's 'need', a sensible rate of weight loss is up to 2lb/1kg a week. However, you can't just train away a large calorie intake than you need. Look at what you are eating and portion size and make some of your own meals. You don't necessarily need a gym, you can train at home and outside.