Being faked online by my bestfriend?

Hi, I really just need advice on this because I'm not exactly sure how to approach this situation. Okay, so I have this person which I consider to be my best friend since I started high school. So for about 2 years. But towards the end of this school year (close to this summer) she's been asking me for a lot of pictures? (Not innapropriate..just normal selfies, yunno) I just thought that maybe it was a step up in our friendship at first, I dunno. But it turns out that she's been pretending to be me online. She normally participates in kik groups and does the "online dating" ig. And usually let's me go through her kik and read her cute role plays and such, but one time I went on her group chat and she seemed quite nervous. She kept scrolling to specific places she wanted me to read and I kept seeing glimpses of the pictures I had sent her.. **slight backstory of the pictures** she is always asking for me to take pictures with the "kik camera" (which is what people ask for to make sure you're not fake) and tells me that she is "introducing" me to her "online friends" and they want to make sure I'm not "fake"? Who wants reassurance that someone's friends aren't fake? I've also been asked by her to take pictures of me holding up the names of her friends online. I dunno, it's just strange and I don't want people thinking they're talking to me when they're not..especially if she's using me for her "online dates" because I have boyfriend which means the world to me and I don't want any confusion. On the other hand MY BESTFRIEND IS LYING AND PRETENDING TO BE ME. I may be overreacting but it's just been getting to me.