Why make plans?

We made arrangements with BM before Thanksgiving for the holidays. She would have her for Thanksgiving week and we would have her for Christmas. Great! She also mentioned due to the snow where they live they didn't want to be driving up & down in the snow (they drive a Civic), this is understandable; so they wouldn't be picking her up the month of December until the day after Christmas and then keep her for the other two weeks of vacation. Cool!
Last week grandma calls and wants her the weekend of the 19th & we can meet her half ways. Then SG calls and wants her the same weekend. So last night I call grandma and she gives me her life story & I listen. I tell her there is no way we can make it out there. If someone wants to pick her up that is fine but we do have plans for Sunday as we were not anticipating her leaving this weekend. We actually had plans for the entire weekend, but to save the arguing we agreed to let her go if they will pick her up. After talking with grandma I have SD call her mom as we forgot to call her back last Thursday (we got busy & forgot). BM asks if she can have SD this weekend, I ask if she is picking her up, she says yes, I let her know about Sundays plans already scheduled. She has to call me back, not sure if she can drop off at time we are requesting. Still waiting to hear from her today. Then I have to call SG and let her know what is happening. Apparently her world got turned around as well because BM called to TELL her they are coming for Christmas. WTH! Are you serious? She doesn't ever take anybody else's plans in to consideration. SG had things to do and apparently after their last stay with her, it got ugly and feelings were hurt (SG's).
SG shared with me how difficult it is to have a relationship with BM. I know, I know. I gotta deal with it as well. After talking with SG for a 1/2 hour I was done for the night but still had work to do. I need to be paid some kind of compensation for being everyone's counselor. This sure does take a lot out of me, thank goodness I have a lot of patience, but it is beginning to wear thin on me. We shall see what happens.