Party kissing problems

Okay so there’s this girl (Catherine) that I would consider to be one of my best friends, we’ve known each other for a couple of years and confide in each other about a lot of things... specifically our love lifes. She’s recently had an issue because she was torn between two guys so ive been giving her advice about it and told her to come to me if she ever wanted to talk. I’ve gone out my way for this girl continuously. Along side this ive confided in her about all the details of my love life, and she had been equally supportive.

However, last night me, her and our entire friend group was at a party. Among this group is my oldest friend Jake and the guy that I’ve been flirting with/ kind of seeing, Noah. One drink led to the next and, as most drunk teenagers decide, we turn to games of beer pong and dares. I had gone inside to grab another drink and when I came out one of my friends pulls me to one side.

“Catherine just kissed Noah”

“Are you sure?”

“It was a dare on beer pong, I don’t know how intense it was”

Fair enough. I’m hurt, but I accept that a- he’s not my boyfriend he has no loyalty to me and b- it’s just a game it probably means nothing. So although I’m upset I brush it off because everyone’s so drunk.

Later in the night I’m in the garage which is now acting as a mini bar sort of scenario with Jake. We’re drunkly wrapping our arms round each other saying how much we love one another, and I’m telling him about Noah/Catherine. Here’s the point I need to state he has a girlfriend, she’s lovely and is extremely good friends with me and Catherine. So Jake leans into me and whispers in my ear

“I need to tell you something”

“Go on then, what’s up”

“Promise me you can’t tell anyone”

“Of course, you can trust me”

“Catherine tried to kiss me earlier when I was in here getting a drink”

...sorry...WHAT. This girl is near enough best friends with Jakes girlfriend and has tried it on with him. Not in any game or dare but of her own accord whilst he was alone in the garage.

Skip forward to today it turns out this girl didn’t just kiss Noah in a game she took it upon herself to follow him into a quiet corner of the garden for round 2 and 3, and I know this because I asked her what had happened after beer pong. Not only had she screwed with me but also Jake. AND THEN SHE HAS THE CHEEK TO ASK WHY IM MAD.

To end, I have to sit next to her in class everyday and not sure how to further approach this.

Am I overreacting? What do I do?

Thanks ladies x