My best friend is anorexic and i try to help super nicely and she pretty mcuh tells me to leave her alone :(?

sounds like she's embaressed. even though you have shown you care by offering help and asking how she is you need to take the next step. if you think it is serious you need to stop being nice and tell her straight up. tell her you dont care if she's embaressed and she needs help. and if she dosent get herself help you will because you care about her. try to have her spend the night then tell her...or hang out...the key is to be alone. stress how much you care and are worried.