Girlfriend (28F) seems like she’s keeping me (28M) a secret

Essentially the title. For a little history, my girlfriend has cheated on her past partners but has made an effort to go to therapy since then and she claims it’s helped, she still has pictures of her exes on her phone and social media, but no pictures of us despite being very active on there, and she hasn’t told any of her friends about us, only her roommate and best friend know because they found out, not because she told them. I have of course told my friends

We recently went on vacation to 2 places sort of road trip distance away (5 hours one way) and had a grand old time. That was that and she goes and posts about it on instagram as she does, which I normally wouldn’t even know about because I don’t use it. The issue comes when I was talking to a group of people in my school and one of them says she saw her instagram post and asks me how she enjoyed the trip (she’s quite involved and outgoing so a lot of people know her) I let them know that it was us, not just her, that went on the trip and then one of them said something that just set me off “oh, you were there too?”. I’m normally a decently calm person (I even had someone ask me if I’ve ever even gotten mad earlier this year) but that just made something snap in me, and I think it was because of how genuine the question was because she really didn’t know I was there. It’s like I realized all of the things in the background at once (don’t know her friends, no pics etc). I’ve been fuming and we recently talked about it but I’ve found a lot of inconsistencies in what she’s said

1) I don’t post my SO on social media- she still has pictures of her exes on her phone, instagram, Facebook, and just solo pics of him too

2) she’s shy- almost everybody knows her in our school, and all of the professors too. She has a rep for being outgoing and involved in everything, and she always says she’s extroverted

3) every time she’s gone on a trip, even it a different section of our city a few minutes away, she posted who she was with

I had a lot of benefits saved up for this year so I used a lot of them on this trip and we really got it good, upgraded hotel room, free meals at a chef’s restaurant, big discount on a luxury hotel and a bunch of little goodies that really made the experience amazing for both of us. I checked her post after I was asked the question from earlier and the only way I can describe it is insulting. Here’s where I get petty but the trip was my idea, I drove 10 hours in 2 days, we pretty much did what she wanted to do (we visited one sight I wanted to see) but I was responsible for the planning and logistics for everything. She’s never shied away from including people in her posts but it feels like she’s willfully excluding me. She only posted solo pics(that I took) and then even cropped me out of some that I would’ve been in, but she made sure to tag the company that made her shirt. I feel like I’m just a prop in her life and this was the straw that broke the camel’s back. She hasn’t told anybody about us and we’re approaching a year together

Am I being childish or just seeing the obvious signs that she doesn’t like me (or probably both)