How to handle this friendship

me and my fiend have been friends for over a decade and over the years I have noticed she copies quite a lot. I said I wanted to start a certain course, 4 months later she’s doing it, I learnt to drive later in life within 2 months she’s doing it, I saved for 2 years for our first home (she told me she had no savings and hadn’t thought of buying) within 6 months she’s got the keys to a house and only told me when she had moved in..

all very strange but let it go over my head until we both got engaged, she got engaged first, then our friend and then me. she messaged me and said she hopes our friend doesn’t get married the same year as her. I then got engaged and she came over to ask me to be her bridesmaid and said I’ll be so busy now for the next year and a half. I then announced my wedding and since then she has not been the same. I am getting married the same year. we are both bridesmaids for each other but if I’m being honest since I announced it shes been different, hardly texts, I never see her, she’s gotten really close with our mutual friends since my hen do was getting organised, she disregarded my other bridesmaid and made a separate chat with them who aren’t bridesmaids. I expressed I didn’t feel as close to them and she didn’t say too much just said let’s start chatting in the group chat again, which never happened after I tried. I feel so distant with her and now them. even on my hen they stayed at hers went home about 12 as they were tired but she later told me they stayed up chatting until 3am!

I feel like she’s just been so unhappy that I am getting married that she actually doesn’t like me and it’s been so clear. before my wedding I asked to meet up to give her a gift but she changed the days and we never ended up seeing each other. her fiance didn’t attend our ceremony due to a wardrobe malfunction and then I didn’t see her for the rest of the day; my other bridesmaids would come over or make effort with everyone but apparently she never did according to family. even in the evening I remember trying to dance with her and my friends and it was like I wasn’t there so I just moved away.

she’s told me in the past she’s very competitive, doesn’t like losing, asked me what my dress was like, flowers etc so that we didn’t copy but I have a very different style to her so I told her not to worry. we also have one mutual friend who is going to both our weddings.

she told me on my wedding that she’s no longer speaking to her parents because of her wedding and she’s stressed. I don’t know, I just feel weird I have asked in the past if we are ok and she just says yeah. clearly not though.

her hen is in a few weeks and i just feel uncomfortable, I’ve paid and I will be going but I don’t know how to be, I’m never off with people but would hate her to make me feel left out. i don’t know.