Family problems

This is very long story and I’m gonna be missing a lot of details not to make this long so I don’t know if I can get the right option from you guys but I’m due in 4 weeks and I’ve asked my sister to come and help me around the house and be around my son so when I deliver he knows who she is and be ok with me gone for 2-3 days at the hospital. My husband is gone right now due to job and she agreed to everything I asked. She came from our birth country and she’s 20. She speaks English since she graduated middle and high school here in the US. Once she came I knew I needed to give her ride to DMV and bank just to get her started here which I offered to and gave her all the informations I knew of these offices. When we went to my moms the other day i asked her if we should get ready and go get these things done and she said she needed a bath and I said ok but after that then because if it’s later than that my son has to nap. She took her time to bathe and on top of that she watched Netflix and once she was ready 2 hours had passed so when I nicely mentioned it’s his nap time but we can go if the bank is around the neighborhood asked her to google the location and she flipped started saying there’s no need because once I get in the car I’m gonna need GPS and that’ll tell me where and how far the bank is.... I simply told her that’s not my responsibility and I work around my sons schedule and she got more and more mad saying a lot of things involving how I need to be the one responsible for her and my son and everything that goes..... so at this point I’m yelling and at the end it got worse to where I left my mothers with my son and I left my sister there telling her if she doesn’t see that she’s in the wrong and disrespectful to how I run daily as a mom then she doesn’t need to be in my house helping us and she said it’s my fault I can’t compromise and that i can’t take on any responsibility then she’s taking herself out of my plate so I can have “less” things to worry about.

Once I got home (4 hr drive) my mom calls me to tell me I need to see therapist because I have stress and anger issues that she’s calling my husband to come home early from work travel because she thinks I can’t handle my son on my own... I asked her if she is on my sister side and she thinks I overreacted and her response was that my sister has right to go places on her time and since she doesn’t have kids she doesn’t know what working around kids schedules is like. But she feels used by me because I’m asking her to watch my son without paying her and I’m the childish one for not letting it go and leaving without talking it out that I brought her here and she’s my responsibility and I need to compromise....... am I seriously the only one who sees this so wrong? My mom and I never had good relationship so what she said doesn’t surprise me but my sister and I talk everyday and we tell each other everything that’s why it caught me off guard when she literally denied my son nap time and told me it’s my responsibility to take her around and know where and how far every place she needs to go to is... who’s in the wrong?