Friend Issues. Please Help.

Okay. This is going to be a somewhat long one so strap in and prepare for the ride.

I have known this girl, we'll call her L, for 16 years. Her mom used to babysit my brother and I for my mom. She had a really rough childhood with loads of abuse from her "step fathers" and was picked on a lot due to her weight (I would never judge her due to her weight!) That's just a little preface to the situation.

So, me and L just recently started talking again after not speaking for a couple months (I felt as though she was unloading all of her mental health struggles on me and I wasnt doing well myself, so I distanced myself). Everything has been going well, and I still am so supportive of all of her struggles and I try to uplift her. But I've noticed she has started to copy EVERYTHING I do. I dyed my hair purple, so she wants to dye her hair purple. I'm married, so she is pressuring her boyfriend into proposing. I'm TTC with my husband of 2 years, so now her and her boyfriend are ttc even though mentally she isn't in a good spot. I have PCOS and now magically without any testing, she has PCOS. She even went as far as telling me she hoped when she gets pregnant she has a miscarriage to be like me. There's a bunch more she's done, but it'd take me YEARS to type it all.

So I guess what I'm asking is, how do I nicely talk to her about all of this? I truly dont believe its healthy to let her think this behavior is okay in a friendship, but I also know she is very vulnerable and emotional, so I want to have this conversation in a nice way rather than straight up saying "QUIT COPYING ME". But it's to the point where my husband wants to say something if I dont..

Please women of glow. Help!!!