Moved out and no time for family?

[RainbowHead]

I didn't know where to post this so I just decided to make it a general topic.

Unrelated to nursing, I'm not even in school for my CNA program yet and I'm already having a hard time keeping up with my family. I moved out to live with my boyfriend and his family a few months ago, been working 30-35 hours at Walmart. As much as I want to, it's difficult to make plans with them because there has to be an absolutely perfect time to visit them, and even when there is, plans get canceled because my grandparents have so many doctors appointments to go to and my mom tells me she's always busy (even though she doesn't even have a job).

Tonight my grandma called and said she wanted us to come see them. I told her we couldn't because we had already planned to go to dinner at his parents. She said well we could come see them in the morning, and I told her I was going out with my mom for breakfast. She then sounded a little irritated, even when I told her I thought the plan was we were going over to see them tomorrow afternoon. They changed their plans on me and expects me to drop everything else to see them. I don't see what would be wrong with staying in town just one more night like they were going to so that I could see them.

It isn't my fault I never get to see them. It isn't my fault they like to change their plans. It isn't my fault I have my own life to live along with having to divide myself between my family members. What's wrong here?