ahhh help again

I posted this the other day but the situation changed. Long story short my bf is invited to a wedding but he lives with his parents so got the invite as a family thing. Well his parents are very close to their niece who is getting married. They are even paying for some of the wedding (his parents only have sons) Wel his grandma asked if I was going and then talked to my bfs mom and idk if they said anything but now the brides mom is asking if I am going and said I'm invited!!! I already said I'm working and can't take off but isn't this really odd? The wedding has been planned for months and his parents already rsvp'd for the food. Shouldn't I have been invited way before all this? I definitely don't want to go since the bride should have invited me and I would be annoyed if someone showed up to my wedding.  Do you maybe his mom didn't invite me or forgot to mention it to me? She's polite to my face but ik she doesn't really like me (heard things, bad vibe).