I'm sorry that is happening to you, but the only person who can control how other people treat you is yourself. If you don't have respect for yourself and your needs in life, then how do expect anyone else to respect you?
1. Eliminate people who disrespect you from your life. You can't change someone else's person's core values.
2. Seek professional therapy! This is very important for taking control of your life.
3. Look up some YouTube videos about how to gain self respect. They work, with time and effort.
4. If someone disrespects you, tell them "You are not allowed to do that to me" or "I don't allow people to speak to me that way" If they continue, stop talking to them completely