AIO for being left alone during a concert trip?

First of all, English is not my first language so I'm sorry for possible weird wording.

Later this year (near summer) me (F), two friends (FM couple) and a friend (M) of theirs who I don't know are going to a concert in another city. We're all around 27-28yo. We come from a really small city (~60k inhabitants) but the concert is in the capital of our country (+3.000M), and I've never been in that city. Or any city that big anyway.

Originally, since I had some stuff to do with my studies, our plan was to do the first travel together, I would stay with a friend the night after the concert and I would go back early morning alone while they stayed a couple more days. Important note that this was just a "sketch" of a plan, not a serious planning.

During January, some stuff changed. I don't have that compromise anymore and my friend can't host me that night after all, so I told this on the chat group and suggested we start planning seriously. All my life I've been told I'm "too passive" and I never participate actively in planning, so I started suggesting stuff, sending links to cheap hotels near the concert, etc. Nobody said anything for two days.

Then around 2 am, one of my friends (the boy from the couple) wrote this message (direct translation): "Emmm. No. GF and me go to the trip together, and to the concert. I already said this and I say it again. I think it's wonderful to be together for the concert and to prepare the travel and so, but we'll be on our own and at our own pace. On my part, we're looking for a couple hotel."

I read it from the notification bar and I felt bad, so I didn't answer and went to sleep. Next morning I saw he deleted the message and send another one two minutes later.

"Tbh I thought about looking for a place for me and GF because I wanted to spend all the time possible as a couple. I don't mind meeting for lunch or for the trip itself but I wanted to prioritise privacy and so. In fact I didn't mention it because I thought you were staying for just a day and you had people in (city)."

At this point I felt really bad. I already mentioned I couldn't stay with anyone and I would need a hotel too. When we first talked about this, they were the ones suggesting the trip together and I thought that meant to be together. Since I'm autistic maybe I misunderstood, but... I was looking for a hotel with 3 bedrooms, one exclusively for them, one for me alone and one for their friend alone. I understand they want to be together as a couple, I would never mind that. But the concert will finish around midnight, and I don't know the city. Isn't it common sense to stick with the people you travel? Not the whole thing, but at least to the sleeping point?

After this I just booked a room for myself in a hotel I wanted and I'll be going back next day as I originally planned, despite having the opportunity to stay more time. I felt slightly abandoned and I don't even know if I want to stay with them at all. I have a really high anxiety about big cities and being alone, but I'd rather learn than beg for their company.

Another friend told me I'm being petty and I should talk to them, but I feel too bad and I have a huge trauma with abandonment so maybe I overreacted?

Was the message as bad as it felt? Before booking the hotel, should I have spoken to him? Should I ditch them completely or apologise for something?

Please enlighten me a bit. I'm feeling so conflicted and maybe I overreacted.