Your height and weight with BMI needs to be calculated. It is good that you do not have any health issues however it would be nice to get a health check done to rule out any possibility. If all is fine you need to work towards boosting your metabolism.
Next Steps
Consult a physician or consult online for a personalised diet and fitness plan. you need a proper activity regime. Some times gym exercises may build muscles and add up to your weight, which may not be harmful. But an individual consultation is needed to help you lose fat and manage weight.
Health Tips
Include aerobic exercises n addition to gym