What do you do when you feel like no one notices you, like your family and friends? What should you do in this situation?

Tell them I'm here and tell a trusted adult that you feel unnoticed and ask why, the adult might tell you to open up more to the world and people and you would probably be noticed. Its ok to fell unnoticed lots of people feel that way, Sometimes being depressed can cause this get help from a trusted adult or get depressed treatment.

c- dynamic stretching

i think the answer is strength