GIRLS- How Can I Fix This?

As far as I know you have done nothing wrong. If she understands your humor then she knows you were just making a sarcastic comment. However, you do not want to seem creepy like you said (I wouldn't call or text again). Something major could have happened to her family, friend, or phone. She also might feel the same way you are feeling... If you know of a mutual friend you could ask them about her.