Resentment and change of heart

Things are getting better. The corrections are working and there was only one major meltdown this week. It does seem like we are constantly describing and correcting controlling and condescending behaviors but there was only one time this week where my son lost complete instructional control which is a win. It seems pretty common, but when it is the end of something fun or exciting my son will have a meltdown. The past two nights my in-laws treated us to the Great Wolf Lodge (hotel/waterpark) for my sons 8th birthday, it’s such a considerate gift, and something we would never budget for being a homeschool family with one income. When it came time to leave, my son would not stop crying, and demanding an answer when we would return. We were empathetic at first, hugging him, and talked about how fun it was, and how special it was, but it was time to accept a no answer. I prepped him with the steps, walked him through it, but three hours he continued to bring it up in different ways earning more and more consequences until he lost instructional control and has yet to start his 24 hours. Another disappointment is that I got sick and because my in-laws have health concerns they have asked us not to stay with them till I get better. My son started shaming me for getting sick, and correcting my corrections. I’m following the script, but I am most certainly a fake calm, not a real calm, I have adopted an unfair attitude towards my son. I am annoyed when he talks (because he always disagrees), He once disagreed to going in the pool for swim team because he had to pee. So I said okay, go use the restroom. He then asked to disagree appropriately to using the restroom. It’s like this all the time.) He notices the way I look at the baby, and he says things like Mommy why can’t you look at me that way? I want to so badly, but I don’t know how to get rid of this resentment I have built up over time. One thing that my husband and I do for each other is prioritize others before ourselves. It works out, when everyone does it. it’s a type of upside down leadership that we want in our family where everyone puts the well-being of others above their own. I’ve realize now that what ended up happening in our family is the most dominant person gets what they want, which ends up being my son. I do want that service oriented, you first attitude in my family, but how do I maintain my role , keep my authority, and still serve. How do I change my heart and find true calm.