I'm so upset 😢

My MIL insisted that DH fly to Alabama for the family reunion since my FIL has cancer and it might be his last reunion. None of that bothered me - what bothers me is that nobody invited me to go and we've been married almost 5 years and are expecting our first baby (I'm 18 weeks). My FIL has always treated me like dirt and like I'm nothing. He treats my SIL like a queen. I'm an RN just got my masters , I'm working 3 jobs, and going to have their 4th grandchild - so I'm not a bum or anything. Idk why he doesn't like me but I'm done caring or trying. I'm not trifling so I'll let them see her when she's born and be a part of her life but I'm choosing not to be a part of theirs. Am I wrong?