Bridesmaid Issues

I have an issue with my bridesmaid. My fiance and I are paying for our own wedding and have everything budgeted out. I have three bridesmaids two of them have been great no issues and very supportive. This is my first wedding let alone having to plan it can be a little stressful but I try to keep it to a minimal. Well I asked my third bridesmaid a nieghbor and friend of 6 months to do my invites since its a nice hobby she already does, she said she`d be happy to mind you I have this in my budget for the materials. Since we have been friends she has taken upon herself to ask me for many favors such as drive her kids to daycare or drive her with family situations all in all I have only asked her to borrow a pan and being friends it`s a give and take situation and I give and give but when I ask it`s hard to get if i am in need. Anyhow she did my invites almost two months after I asked she offered to pay for the materials and I told her I could its in my budget she said no problem I got it, I figure nice gesture. Now she is complaining about the invites and the time i needed them (only 25 of them) so I thought no big deal, but she said it was stressing her out then she forgot 2 inserts and when she brought me those they were sloppy so I asked her to fix them. Now she is stressing me out and for the dress fitting she cancelled on me just because taking my time away and had to reschedule so I had to reschedule my plans to go with her. She brought her daughter who cried because my daughter is my flower girl got a dress and she didn`t so she bought her a dress and tried to hint she should be in my wedding too. She keeps hinting how she is doing me a favor by being in it and complains about her time being used up. I feel alot of unneccesary stress and want to just dump her before it gets worse......I need advise, sorry this is long if I drop her how do I do it ....I am horrible about hurting peoples feelings but I am way to nice