I get jealous and angry knowing my boyfriends mom loves him and his sisters more than me. What should I do?
That's pretty crazy to feel that way. Why would you be jealous of someone for being loved by their family?
Its not good to be loved by someone who is so full of shit.
An overpowering nature is the sign of insecurity and domination, and has nothing to do with your mother in law but actually is within yourself. Speak to your boyfriend about your feelings and get in touch with what's important.
Why does she have to love them? I just want her to love me like her own kid.
She might learn to love you but if you keep harboring these feelings it's going to make it tough for her to feel that way with how crazy you are acting.