SIL: am I being crazy?

So my sister in law has never really liked me and she recently got married and didn’t invited us. For reference my husbands family is just him, his sister, and his mom. They weren’t close growing up due to divorce but I have always tried to make her part of my family and include her in everything holidays birthdays girls days etc. I have 2 sisters of my own so I know how fun it can be to have sisters and she has always said she wishes she could have that. Well I’m not cool enough for her and our personalities don’t mesh enough for her. Anyway so she literally said she didn’t want me at the wedding but wanted my son there and my husband she didn’t care if he went or not. Mind you I have never once said or did anything negative to her because she’s my husband’s only family. So now the wedding is over and we all went and she told me to stay out of the family pictures asked me to leave early because I wasn’t needed there anymore. I kept my cool and was like “thank you for having us and congratulations” then left. Now I’m going on vacation in October and she invited herself to our house to watch our son with my MIL but I don’t feel comfortable with her being there without me because I know she doesn’t like me. I just don’t think I need that negativity and don’t want someone who doesn’t like me in charge of my baby while I’m away. Am I over reacting?