Am I overreacting?

hello, I need advice!

I’ve been friends with my best friend since elementary school. we are now college roommates. I planned a trip for the three of us (including my other best friend who is also a roommate). I’m graduating this semester so I won’t be living with them. I wouldn’t mind living with them again but my one roommate is going to live with her bf and my other (who I am talking about today) has decided to live with her other friends.

Anyways, I wanted to take a trip because my best friend (we’ll call her Tanya) went on vacation with her other friends for spring break and I didn’t get invited. So, I asked Tanya when she could go and she said April 7th to the 9th. I found a place to book, asked my other roommate if it was ok and we all agreed. I booked the place, sent the details by email, text in our group chat and even mentioned it in person. I have been really excited because I haven’t gotten to take a trip yet. Then, today, Tanya sends a birthday surprise party pic thing to our gc and it’s on April 7th. I was really confused and my other roommate was like “isn’t that when we are going on a trip tanya?” Tanya said she forgot and when I confirmed that it was when we were leaving. She said she wouldn’t drive separately the next day. I’m really sad because we’re only staying at this place for two nights and she is ditching us for her other friends (who’s she’s living with next year btw and sees literally every day).

Am I overreacting? I know I seem jealous and I am to an extent but past that we planned a whole trip and she’s gonna miss an entire day for one party. Am I in the wrong for being upset? What should I do?

Thanks for 📖