Receiving and giving. Most of us like to give and don't expect something in return, It makes them happy and gives a good feeling to do something for others. Wich is good if it is
in a good balance. Giving makes us capable of receiving positivity back so it can keep us in balance.
But sometimes giving becomes too much even if the good feeling stays, a lot
of people don't realize they give too much. But what is too much.

Giving a lot to others means actually helping others with big issues to small troubles. Wich can cause trouble with your own energy level, because even if we give we expect something in return back aware or unaware doesn't matter . We still keep giving.  For HSP people under us this is a daily issue and very difficult to get rid of.
For HSP people it is important to stay with themselves, and to listen to the feeling is this / that good if I would do it ? If the feeling is no then don't, especially for young people it is good to do so.  Protecting and shielding your own energy field is a trick what I always do if I sense that someone wants to use my energy for something so it is for the other person easier.

Remaining positive and staying close to yourself is actually a start for receiving ( you receive positive energy )  then the rest comes all by itself.