Sister is jealous of gender or what ??? Help me !!!

💙👣👶💑👧💉 • I am a mom to 3 angel baby's and 1 living child .I am currently pregnant and on lovenox with my 🌈rainbow 🌈 baby boy impatiently waiting his arrival.
I am pregnant with my rainbow baby and its a boy ! I am ecstatic ! I knew my sister wanted a boy really bad but has three girls so I felt as though I had to guess it was a girl so she would be less mad at me at the gender reveal. When the blue balloons came out she and her husband got weird looks on their faces and said nothing :( I was honestly just as surprised as them as we have a girl and mostly girls run in our family . No one cheered no one was excited no one made a big deal . I felt cheated out of my moment . Is it wrong to want to distance myself from her ? We have a strained relationship because she is always blaming my daughter for being mean to her daughter but in reality her daughter is the one that is being mean to my daughter but if I say anything she defends her daughter agressivly. My child goes to public school and plays with all types of children and has never had any issues getting along with them . When I picked up my daughter from my sisters house from a play date she sobbed the whole way home . I ask her what was wrong and she said that they boss her around and make her play things she don't want to play then never play what she wants to play. Her daughter is verbally abusive to my daughter( I have seen it in many occasions) so she sticks up for her self. My sisters daughter wont play with Ryleigh in front of me and always takes her to a place where i cant hear them but when i go look for them and find them my daughter always is frustrated or already crying .I am so stressed about this :( I do ALOT for her and she never returns the favor and I feel used :( I was over there working all week to make her life easier and she had the balls last night to ask me to come tomorrow and watch her children so she can go on a trip to see her friend. Also I was supposed to tell her Mexican maid how to clean the house in Spanish ( I know little to no Spanish) I finally got her to see that I was tired and needed a day off but I still feel like she is oblivious to my needs . I'm 4 months pregnant ! I worked my butt of all week . My own house has suffered greatly and looks like a pig sty . don't she get it ? What would you do ?