Not diagnosed with an Eating Disorder: girl, 15. Social worker? Please help!?

You should most definitely let your parents know how your feeling, and accept the offer that has been given to you so you can figure out whats going on and stop the routines you have been doing so you can live happily without all the worrying. Your still young and there's plenty of time to figure things out, but sooner then later is always better. A social worker is there to help you, sometimes you may need to see different ones until you find someone your comfortable with. Good luck with everything i hope it all works out:)