Hi,
The present weight you have is fine according to your height. To reduce belly fat and other specific area you need to do specific exercise along with following a balanced diet, but right now may be your body is not recovered fully so for that reason you should follow a nutritious diet, rich in good in protein ,fruits and vegetables. Hydrate youself properly and don't keep gap more than 3-4 hours between meals. Try to add cashew or almond in your meal which gives you energy. There is hormonal changes occur before starting periods, which may cause some times mood swing, less active, feeling low. You can keep yourself engage in different activities, it will helpful.
Next Steps
You can chat directly with me on practo for further discussion.
Health Tips
You should have a sound sleep about 6-7 hours.