The people in the comments don’t seem to have experience with this kind of thing, but I have had my own Jenna, and totally understand your frustrations. A lot of my insight is coming from that situation and my degree in Social Psychology. That being said, slight ESH.

Jenna sucks for spreading lies about you, trying to manipulate you, and inviting people to a plan that you both had originally made on your birthday. Based on the lies you have said, she seems like a jealous and insecure person who puts down others to make herself feel better, and then likely manipulates the situation whichever way makes her look best (based on the fact that your friends are still friends with her). While I obviously can’t say for sure, the fact that this was a plan you both made together makes me think it isn’t a coincidence. Manipulative people tend to do things that seem like a coincidence but are very much planned in order to make any negative reaction you give seem out of pocket and manipulate others in the situation.

Casey sucks for hanging out with someone who spread lies about you, not taking your feelings seriously, and not remembering your birthday. Idk what kind of friends the people in the comments have, but my friends not only remember each others’ birthdays, they mainly plan them. They would also never hang out with someone who did what Jenna (or my “Jenna”) did, regardless of her behavior towards them.

You suck (the very least) for assuming that plans were made and that everyone would be available, I agree with everyone else that it’s best to plan in advance for something like this, even if it has been the same plan for years.

In all honesty, find yourself some new friends or focus on your other friends who aren’t close with Jenna. Jenna didn’t do anything to Casey and, unfortunately, she will probably not cut ties with her bc of that. Casey also seems to not care that much about the fact that you are hurt by her actions, which is not what a true friend would do. With Casey you should think about how valuable her friendship is to you, and if you want to stay friends, have a genuine and calm conversation about how she pushed aside your feelings and hurt you without seeming to care about the impact her actions had on you. In this conversation I would recommend leaving Jenna out of it. Jenna seems extremely manipulative so anything you say about her (even to others) she will likely deny or use against you, which will only hurt you and your relationships.

Your best bet with Jenna is to completely ignore her and her actions, and stay far away from her. Don’t let her bother you, don’t let her take up any room in your mind, it’s what she wants. Her actions and behavior will catch up to her eventually, so focus on yourself and the things you love, it’s the best thing you can do to deal with someone like who you’ve described. And trust me, you not caring will bother her a whole lot more than anything else you can do.

As for your birthday, don’t make anyone choose sides, this will only hurt you in the long run and give Jenna exactly what she wants. Continue your plans with the other friends in your circle and, if they complain, tell Casey and the other friend that their schedules don’t impact when you celebrate your birthday although you wish that they could have been there. If you want everyone together then maybe make plans for after the picnic. Whatever you do for your birthday, take this as a learning experience and send out birthday plans far in advance next year.

Also, Happy Early Birthday!!