This one can be easy to miss.
Maybe they mentioned a restaurant they want to try someday. Perhaps you talked about a movie, and they said you should watch it together. Maybe there was a casual “We should do this again” somewhere in the conversation.
It may not have been an official second-date invitation, but future plans slipping naturally into the conversation can be a sign that they were already imagining seeing you again.
And honestly, sometimes that is all the reassurance you need.
A first date does not have to feel like a scene from a romantic film to be successful. If the conversation felt comfortable, the interest seemed mutual, and neither of you was rushing to make an exit, there is a good chance you are being much harder on the date than it deserves.