How should I take this?

So I have been seeing this girl for the past 2 weeks. I've seen her 3 times with the last time being Friday into Saturday morning. All 3 times were really great and we have amazing chemistry. Ever since the 2nd date we've texted more. She even brought up wanting to go to the movies as our next date Saturday night. Yesterday though she was really low energy on texting and was doing a lot of short responses. I didn't reply to the last thing she said which was just hahah. I haven't heard from her since. Should I take that as a sign that she lost interest since Saturday or am I just overthinking?
How should I take this?
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