Can I lose 5 kgs in 2 weeks by just drinking 2 litres of water per day?You are 16 years old, and you have a serious medical condition that is linked to your hormone levels. You say it is "under control", but it still has many serious long-term implications. Your weight and nutrition are important factors in dealing with your condition for the long term.
There are two things that you should definiitely not do:
Rule #1. Do not make any changes in your diet and nutrition without consulting your physician and/or a registered dietitian that your physician has referred you to.
Rule #2. Do not ask Quora, any other site on the Internet, or any other group of amateurs who do not know your entire health situation, including history and current test results, for permission to violate rule #1.
Apart from that, starving yourself for two weeks, at any age, even if you are in perfect health, is a terrible weight loss strategy. It is dangerous, and unlikely to result in lasting weight loss.
Furthermore, the number of actually good reasons for losing that much weight so fast is very, very small, and you've given no justification for why your reason is valid. You haven't even given the reason.
Don't do it.