Maid of Honor causing Major Drama & Stress

So I'm not sure if I'm posting this in the right section or not - if this is the wrong section, I do apologize, but I hope someone can help me anyway! So, my maid of honor is someone I have been friends with since freshman year of college when we were roommates. Although a bit overbearing as a roommate, we became better friends once we no longer lived together. I was having great difficulty picking a MOH and asked her. First, she was hesitant to accept as I live in NJ and she lives in FL, but she did accept with the understanding that I don't expect her to do much at all. I have 6 other bridesmaids that can help plan things, and they are more local. My wedding isn't until June 2019, over a year in the future. Well ever since I asked her to be MOH she wants to talk every single weekend about "details" and when I tell her listen this is all I have figured out right now, she continues to ask for details. Which is frustrating. To make matters worse, she will text me hello and asking how I'm doing and when I respond that I'm a little stressed (of course asking how she is doing also), she responds with "everyone is stressed out and busy, you're not the only one who is, stop making it out like you are it's annoying." This has happened multiple times now. I have tried multiple times to call her and talk on the phone, and she isn't available when I am, and I'm not available when she is. Yes, everyone does have busy schedules. I ask her when she's available to talk in order to attempt to try and work something out, and she refuses to work with me, only mentions one date and time and as luck would have it, those never work for me. I hate drama, and this all may sound petty to anyone reading it, but this has been going on for 6 months now and I'm at the end of my rope. This person is very rigid and holds grudges over small things -- the true definition of "makes a mountain out of a molehill" amplified by about 10. I have tried to be understanding with her as she has never had a romantic relationship before and has a difficult life and not many friends. Honestly, I thought asking her to be my MOH would be exciting for her, something to look forward to. I offered to pay for her plane ticket and hotel, and explained that all I need from her is that she shows up to the wedding and also it would be nice if she wouldn't mind making a toast. At the time, she turned down my offer to help financially. Aside from being busy trying to book vendors (June wedding vendors book up fast here in Northern NJ), I have on average 3 doctor appointments per week due to the fact that I have several serious physical health issues including Crohn's Disease which I'm still suffering the symptoms of depite being "in remission", plus a full time job that requires my attendance at some evening meetings. I truly am a busy person, as are many people (obviously) but I feel like when a friend of 11 years is asking how I'm doing, I should be allowed to tell her that I'm busy and stressed and hope to talk to her soon. However, as I said, every time I attempt to have a real relationship with her, I am met with bitter resentment and invalidation. Now, she is complaining about being my MOH, says she regrets agreeing to it (!!?!) and is complaining about the cost of the wedding, and saying outlandish things like "weddings are only expensive for out of town guests"....I've been to 10 local weddings as a guest and they were ALL exensive...not to mention being a bridesmaid or MOH which is more expensive. I'm just really upset....I have done all I possibly can to make it easy on her to be a MOH and not a stressful experience, and all she is doing is complaining and making me feel like s***. I apologize for venting but felt this community of fellow brides would be the best place to do so. Finally, I am wondering...does anyone have any advice for me...would it be appropriate for me to ask her to step down from the MOH position since it's obviously causing her so much stress, and tell her she can be a regular bridesmaid if she wants? I can't do this anymore. My physical health is just not up to the pettyness. I'm usually a low maintenance person and the whole act of wedding planning isn't exactly a walk in the park, but I"ve been trying to be as accomodating to my wedding party and guests as I possibly can be and it's really off-putting to have someone attack me almost every day over such trivial things, especially when I am doing all I can to make time for her and make things easier for her.