How can I help my daughter adjust to the new baby?

I’m in desperate need of some advice. I just had a baby girl 3 weeks ago. This makes child #4 and girl #2. Her older sister who is 4 is having trouble adjusting. She constantly asks me why her baby sister gets to “do stuff” and she can’t. Ex: why does baby sister get to sleep in your room and I can’t, or why can baby sister get to drink at night and I can’t (we stop drinks after a certain time to avoid the frequent bed wetting.) And asks me why her sister gets to stay up and she has to go to bed, and if I try to explain it to her she throws a tantrum. This new baby is the only one I’ve been able to breastfeed exclusively and she requires alot of time and attention also me holding her every hour to feed. My husband works out of town all week so is only home on weekends. It’s been extremely hard for me to balance a new baby as well as my three others. How can I help her adjust. She doesn’t seem to be jealous of her baby sister for the most part, always wants to hold her, and help pick out her clothes, constantly wants to look at her but these tantrums seem to be getting worse and no matter how much I try to talk to her about how baby needs certain things or how she ‘gets to stay up’ bc she needs to eat, the madder my daughter gets and just starts screaming. It’s very overwhelming and I constantly feel guilty because she seems to be hurting. I just don’t know what to do anymore. Sorry for the long post I’m just so lost. Any advice is appreciated!!