I would suggest therapy & through therapy getting involved in DBT....group setting specifically. It teaches us skills that for some reason we didn't catch onto or weren't taught growing up.

It teaches us mindfulness...awareness of our emotional & logical thinking & putting them together to come up with wise decisions on how to handle situations or problems we find our life in.

The interpersonal effectiveness I think would be key to your situation. It helps us learn how to interface is an effective way with others. To learn how & when to ask for things we need & how & when to say NO to those asking things from us.

It also helps with emotional regulation (controlling our emotions & letting them out in appropriate ways....recognizing that all our emotions are there for a reason).......& distress tolerance (how to deal with distressing situations we find ourself in in life so that we don't make the matter worse).

One thing that hit me was please don't "put out" to get people to accept you. If they don't accept you for who & what you are....you don't need those kind of people to accept you...you are better off without them in your life.

Know it's difficult to see the rest of your family be accepted......I think therapy could definitely help you learn what's missing in your life that is causing that to happen. Maybe it's your perception of what is happening. Or maybe your family treated you as an outcast & it's been what you have taken on as your feelings about yourself. If you are the youngest, sometimes that happens......

Think therapy would be your best help in your situation.....with DBT as it's focus.....just my suggestion. I didn't have the same problem as you have, but I know how much DBT has helped everyone I know including myself no matter what their issues have been.