Copycat friend.... how to deal in a very nice way.?

help! she buys the exact dress that i wore but in a different color. she buys the clothes that i'm wearing. she copies the shoes, bags.... i'm like upset already. i'm glad to show her that we can be feminine in a good way but not to the extent of copying me. now, she's on a diet coz she wanted to have my exact weight :( .... that i don't mind but, i don't like going out seeing a carbon copy of me. it's hard coz i've been dressing myself up like these even before we bacame close. i'm so annoyed, paranoid and unhappy. help help help