Why do i feel sad about this?

well i have a friend who thinks i am never there for her. A couple of times she wanted me to do something for her and someone else had already ask me to do something for them and she feels because these people are never there for me and she thinks they are users i should just drop what i am doing for them and do what she ask me to do. The other day she ask me to watch her baby and go to work for her while she goes to wrestling match in Iowa for a couple of days. I agreed and said yes but my sister ask me to borrow my car and go pick up her daughter who got beat by her daddy and dcf was about to take her . I let her but she got stopped by the police her license was suspended which she didn't know they took my car she got stranded and so i had to take her baby over to the live in granddaddy and i called her and explained to her what happen. She called back and said the father of the child who was with her thought that the granddaddy would have windows up and give the baby a cold. So i called the babysitter who she uses all the time and ask her to baby sit while i was gone and i would pay her and she said yes. The baby sitter who she uses all the time said the baby fell on floor and started crying the baby didn't get hurt but they drove all the way back after the match was over and was very upset . She didn't say she was upset but she said stuff life she feels like she has no one. She said if i dont help her she cant call no one else. Yes i been there for her before she has lived with me and i have did plenty of things for her before , like i have give her money and did things for kids and a lot of others stuff. But i think she feels i am not there for her. I was thinking of my niece and my sister but she was thinking my sister is never there for me and she was probably lying and stuff like that.