I am getting married in November, and I am having some serious MOH drama. I don't know how to handle this situation- please help!

I got engaged Fall 2016, and asked my MOH to be in my wedding in December. She knew about my wedding in almost a year in advance. So, this summer she got engaged, I helped her now fiancé pick the ring and plan the proposal, and I was so so excited for her. They have set their wedding in Spring 2018.

I told her I would help her with anything, give her anything of mine if she wanted to use it so they could save money, etc. She jumped straight off the deep end, straight into bridezilla mode. We have a mutual friend, who is in both my wedding and now also hers. She cut us both out of everything, picked her dress and didn't even tell us, (when she was angry with me that I went into salons to look at their selection to see if I wanted to make an appointment there or not) demands that we make these signs for her, etc. I have never made anything "required" for my bridal party, not invitation addressing help, not the dress appointments, vendor things, or DIYs I decided to do. I have instead told them they could come if they would like to (my bridesmaids usually do) but it isn't required. I tell them OFTEN that just because I'm getting married doesn't mean that their lives stop. They were my friends before bridesmaids; THEY ARE NOT EMPLOYEES. I found a bridesmaids dress I fell in love with, but it was way way over their budgets (we are mostly broke, college aged) so I scoured the internet until I found one I liked pretty equal for $30. $30. Way under their budgets btw, and they were thrilled and they all actually like the dress. I made sure they could sit, squat, bend, dance and all in it and they felt good and confident. I haven't made hair or makeup required, and the dress is long so as long as they are black, they can wear shoes they already have. My MOH (knowing that our price points are similar to those of my bridesmaids, and she picked the very same dress for us. Demanded that it be ordered ASAP, and had a very fake concern if we felt okay in it. Meanwhile, her mom made nasty comments to me about how my wedding will look like a thrown together get together in comparison to her daughter's "elegant and classic southern wedding" (knowing my theme is classic/ rustic elegance) That covers the Bride clash.

Now, I'm 2 months from mine, and she is one of the people planning the shower, along with a family friend and our mutual friend. My family friend has offered to pay for everything, the food, decor, etc. she offered to do the invites anyway my MOH wanted, but she said she had that and the decorations and cake covered. She planned my shower originally over a holiday, so she changed it. (NBD, it happens and invites hadn't been sent.) so here we go, and the family friend is asking for the RSVPs. So my mom calls my MOH for them, and 3 weeks from the shower, she still hadn't gotten the invites. Not printed, not addressed, not in progress. So after sending my mom and the family friend to voicemail REPEATEDLY over the week prior, she finally answered and then jumped on and created a half assed word doc looking thing, with half of the information missing, etc. She said she was going to do it, just didn't think about it so on so forth. So my mom says, NBD, let's just move it back a week and then we'll be in the clear and she says "I'm not willing to do that, I'm celebrating my birthday that day." After she's planned stuff and events like bridesmaid dress shopping over my fiancé and I's anniversary plans (which she knew about in advance as well, she and her mom planned over it.) so she wasn't willing to budge on that. So last minute, (my mom was under the weather and my family friend was out of town) because she couldn't be bothered, and said she was unavailable to do them that night because she had plans, I had to go GET MY OWN INVITATIONS, fill them out, and address them because it was going to be a weekend and wouldn't have given the guests enough time to RSVP and make plans to be there. I also find that she hasn't gotten any of the decorations, and hasn't made any arrangements for cake/cupcakes yet. (Currently 12 days until the shower.) She also plans the bachelorette party, hypes me up and then I find out that none of my bridal party will even be in town this day, because she didn't tell them when, or ask them. So she rescheduled it to the weekend before the wedding and I politely said "I don't think that would be the best option, I'd like to have that weekend free for any wedding related emergency stuff. How about the previous weekend?" She said she wasn't willing to do that because she already had plans, and basically if we didn't do it the weekend before the wedding, I just wouldn't have one. (Not a huge deal, but it's more about principle I guess.) But she's taken days off work to go hiking, and whatever, and couldn't be bothered to go with my to anything(if she did, she only talked about her wedding, her colors, dress, theme, venue, flowers, so on so on), while our mutual friend has gone above and beyond (acting like my MOH should) and when I mention talking to her, she avoids me, gives me attitude and makes excuses. She wasn't like this before she got engaged, so idk what to do. I'm so conflicted because she was my best friend. What am I supposed to do? I'm so sorry this has taken so long- thanks for reading if you got this far!! Any advice is appreciated. I hope I don't sound unreasonable.