PS You said that the girl said that she was having racing thoughts. I am not sure what you meant; racing thoughts are a very strong indication of a psychiatric disorder. If she told you that she was having racing thoughts, and if in Spanish racing thoughts are indeed a psychiatric syndrome, then that means that the girl has a mental illness, is knowledgeable about it, and is completely open about it. I doubt that this is the case - it is one thing to have sex with a boy after one week of knowing him and another thing to talk about one's psychiatric condition in professional jargon after such a short period of time knowing a new person, so I doubt that that was the case, but if it was the case, the girl deserves credit for not yielding to stigma.

On a more serious note, I am unclear as to why you started doubting yourself and even treating this as an issue. I do not see any issues based on your evaluation of the situation which you made before the self-doubt started.

You wrote that she was perplexed. That sounds exactly right. Appearing perplexed fits the situation. It is the most likely reaction.

You wrote that she did you dislike you. Nor that she liked what was happening.

Which is in line with saying that she was in neutral.

And then on the one hand she said that it was too much to deal with.

And then on the other hand she was relaxed enough to continue on and even have an orgasm.

So yes, confused, perplexed, a little bit of this and a little bit of that - neutral. It was not a negative experience - not extremely positive, but not negative, either. A tie - you can continue on with the girl and things very much can improve as the anxiety level subsides once you settle into a familiar, routine relationship, or you can call a day with the girl and move on to some other things, but treat it as a neutral experience and not a fiasco.