mama drama

Kiara⭐️⭐️⭐️ • 26. 6.9.2017 🌸 due for #2 08.23.2020
I honestly feel like i have no one to turn to for advice on this matter. My mom has been my only parent for 23 years of my life. For the last year, i have had the most wonderful boyfriend i have ever had in my best friend of 6 years. His family is so supportive & caring of me & they include me in literally EVERYTHING they do. So when it came down to planning the baby shower my mom was all for it until i shot down a venue for being too small to accommodate everybody ( including my boyfriend's large family). Suddenly it became an issue of her not wanting to feed a big amount of people & not wanting to deal with a larger family. I know she has always been anti social but it's gotten to the point that her comments have gotten out of control. She decided she didnt want to deal with the baby shower anymore & was going to let his family take care of it. 
So now everything is decided about the baby shower. She now starts making comments about how all i care about is his family & im shooting her ideas down regarding the baby shower. ( mind you: she decided NOT TO TAKE PART IN THE PLANNING.) when i explained that to her she gets all up in her feelings & it's adding so much stress on me dealing with her & trying to not to hurt her feelings. 
I've been invited on a trip with my boyfriend's family for his uncle's wedding which is the day before my mom's birthday. They are leaving after mother's day. I feel like if i decide to go im not going to hear the end of it from my mom if i miss her birthday. I honestly dont know how to handle this situation. Somebody dealt with this & have some advice?