How Does Intermittent Fasting Promote Health and Weight Loss?

I have been doing intermittent fasting for the last 3 months. In the beginning there was no problem at all. But recently I am facing frequent stomach pain. Is intermittent fasting the reason for my stomach pain ? Does intermittent fasting really causes stomach related problems ?

I need to know whether intermittent fasting is good for our health? Can you please tell me pros and cons for it? Is it dangerous? Does intermittent really flushes out the toxins?

I was a few kilogram overweight so I started 1-hour exercise and intermittent fasting a few months back. I have lost around 5 kgs and everything was fine till I noticed that my period is 3 days late this month (which never happened before) and I'm facing a hair loss problem as well (from the past few months). My fast time is 9 pm to 2 pm (17 hours). I don't consume any solids during this time, just tender coconut water at 12pm (which means after 12 hours fast). I have nutritious food at 2 pm and 8 pm and work out at 11 am and 6 pm. What am I doing wrong? Should I stop IF? Or should I continue?