transitioning from one kid to 2 help

im struggling here. i was so used to it just me and my first but now that the baby is here my daughter isn't the same. she wont put her shoes on the right foot,she takes the babys stuff and hides it,she cant put a seat belt on anymore,shes now trying to tell me to shut up😒 i dont spank i do mostly time out or talk to her but lately i realise ive been yelling at her more ☹ I'll admit it and im not proud of it but im just

so stressed out with my now 4 month old and my 5 year olds behavior.she also has a speech issue and understanding somethings. i tried preparing her and having her help with her sister. ove even put her in multiple sports activities so we can practice and have one on one time but idk. i feel terrible yelling at her i already talk loudly as a person but this is not the kind of parent i want to be... any advice on how i can work on myself or help my child.