For your mental health and sanity you must walk away from ungrateful people. I don't care if it's one ungrateful person or a thousand of them, you must walk away from them and seek only to have relationships with those individuals who are grateful to have you be part of their lives.
If you allow yourself to be surrounded by ungrateful people they will drain you of every drop of energy you have and when you have nothing left to give, they will leave you lying on the ground bleeding and dead.
Do not fear living alone because it is better to live a life alone than live your life surrounded by even one ungrateful people who only want to take from you and is unwilling to give you anything in return.
To live a balanced life you must both 'give and receive' and if you are giving and no one is giving back to you this will cause you to live an unfulfilled life full of resentment and bitterness.
The fact is any time you feel resentment or bitterness that should serve as an ALERT SIGNAL to you that you are living an unbalanced life.