The first thing you need is motivation. Laziness is just not going to help.
Second, how fat are you. I'm asking because these days 40 kg women are calling themselves fat 😛 anyway, increase your metabolism. Drink warm water with a spoon of honey early morning. And don't eat after 7 pm. Keep yourself full by eating lots of vegetables and fruits and do routine exercises. This will help you out without the need to hit the gym.
You go girl!
Get urself checked ur BMS and thyroid also... U need to find out the reason fr ur weight gain first... H cn hit the gym but I wud suggest u to do yoga and walking jogging dancing best to keep u in shape...trust me I myself tried it 🙂