Advice: My parents forgot my birthday

I can't believe this!Is it possible for parents to forget his or her child's birthday?I celebrated my birthday three days ago;my dad and mum couldn't even call me on my birthday.It was on the 2nd day,early in the morning that my mum now remembered.She started pleading with me that she forgot.Seriously,Is that
possible or has it happened to anyone before ?

What should i do ?
Because right now i feel like leaving them to start a new life on my own.