I need help! & serious advice !

I need help so this is what I’m facing. I’m going through a phase of my mom staying with me !!! It’s kind of not working out. I’m homeschooling my kids and now she’s being a distraction I’m having to run her here run her there. & she’s throwing off my schedule of homeschooling. I just purchased a vehicle because my sister got rid of hers now she’s needing a ride from me. Everyday to go babysit my sisters kids and I feel they should come get her each day. My truck head gasket might blow out any day and she’s still asking for rides. I don’t have a mean streak in my body I hate telling people no and then when I say no people act like it’s being mean but in reality I try not to be mean but if my car break down no one is going to help me fix it. What should I say in a nice way like hey my guy is coming to fix my car and I don’t think I should drive it so it don’t break down. But she might take it the wrong way and start not to like him because she’s always thinking negative I’m not going to like her reaction but I’m not going to be able to drive it unless it’s a emergency.... and her runs aren’t a emergency and she’s throwing off my sleep schedule. I’m having to wake my kids up 4:00 each morning. Drop her off come back and then whatever we decide to do and it’s becoming a everyday thing ... Monday through Friday then I take her to work on the weekends and it’s 5:00 6:00 am each weekend it’s draining me and I barely have time to teach class for homeschool because my days are filled with her but I want this to stop it’s getting out of hand my sister boyfriend has a car. I’m getting frustrated with her washing clothes every weekend for just her uniform which is one shirt and a pair of pants and she don’t pay any bills here. What should I do ? I’m so tired and frustrated