Answer:
Low self-esteem
spending a lot of time alone
Reluctance to let parents or other family members anywhere near their mobiles, laptops etc
Finding excuses to stay away from school or work
Friends disappearing
Losing weight or changing appearance to try and fit in
Fresh marks on the skin that could indicate self-harm and dressing differently such as wearing long sleeved clothes in the summer to hide any marks
A change in personality i.e. anger, depression, crying,
Humans need to eat and drink in order to survive, therefore it against natural law to deprive oneself of food and water, as natural law says that species must survive.
I'm not good with religious things, but I think this might be helpful: https://www.wikihow.com/Confess-Sins
If someone is important to another person that means they make good promises, always together, and see each other a lot. Hope this helps!!!