Prego hormones, feelings are hurt 😞

My little brother took his new girl friend home to meet my mom this weekend and we all know their relationship is moving pretty fast (he's 30 and has made it pretty clear he's ready to settle down and start a family). I text my mom a few times this morning asking about the visit and I got short answers. I just heard from my sister who asked if I'd talked to our mom today and I said briefly, why? She had just gotten off the phone with her and mom was all excited because our brother proposed at dinner last night. I'm so hurt, why didn't my mom tell me?! I'm not surprised my brother didn't announce it to me yet, he's not real great with communicating so that's whatever. But I'm really hurt that my mom told my sister but couldn't tell me two hours ago when I talked to her and specifically asked about how things had been last night. Am I overreacting?