Gma to watch Gchild, feud happens with other Gma

I was asked to watch my grandson (almost a year old) while my daughter and son-in-law went on vacation. What an honor! I was told beforehand some issues with boundaries with the other Gma, who was angry that I was asked (she actually sees him more than I do, but it isn't a competition for me), wanted to visit while they were gone. I was given a list of situations that would not be allowed with her. Time alone over a few hours, being firm with their time together if he was upset with her (I was told he is afraid of her, and she has been told not to use certain voices, etc.) and a few other problems that may arise. She contacted me about coming, and when she got there, it was obvious my grandson was afraid of her. He kept wanting to be with me (was I supposed to ignore him or say no?), so I held him while she played and talked to him and he was ok. What I didn't know was that she had insisted on coming over, and staying until our kids came back. I was very uncomfortable with this. No mention of where we would sleep, who would do what, and if my grandson didn't like her, how many conflicts would arise with feeding, etc. The other problem is that she just wants to play and despite stating he is hungry, diaper needs changing, he's tired, she doesn't stop, so I would need to do these things by insisting? I don't know her that well, and with the problems with his parents being what they are, I tried to subtley enter phrases of goodbye, going to see you in a couple of weeks, etc. I heard goodnight and yes to those, and nothing direct. So I asked directly if she had planned on staying. She said yes, and when I explained that I didn't know, she started getting angry and said her son said she could and she was staying. I left the room for a bit. When I came back, I told her that I wasn't expecting this and she needed to leave. She said no, so I told her she could stay but I would take my grandson with me to my home. She wanted to get his parents involved who were enjoying their first vacation ever in 10 years, and I said that wasn't a good idea and why ruin their vacation. She stared me down, than left saying her son would hear about this. Which she did later (2 am). I am a reasonable person. If she had even suggested that she understood there was a misunderstanding and asked me if we could work it out, I would have felt more comfortable. Our kids discussed it with us, then each other and said that we need to work it out between us, and that there was miscommunication, that her son knew about sleeping over, and I should have given her more time and not thrown her out. So, I contacted her to talk, and she said ok, but later because she was going to a party. Then later that day sent me a message the party was cancelled and that I could call her or she could call me. Well, the original idea would be for her to call since she would know when she got home, and I was home all day. I want to swallow my pride, but I feel stepped on, and that blame was balanced on both of us, and maybe SHE could reach out and call. I just lost my husband, I am disabled, and I am tired of feeling like the bad guy (anyone familiar with calling about 401k, life ins, etc, may understand not all of these companies are nice to you). My next step?