I didn't reply to a girl for about two days and now she seems to be angry, what should I do?

Animeboyy
I like this girl quite a bit and she usually replies to me very quickly, however, I went home from college and didn't really have the energy or time to text her for about two days. I had some time yesterday evening and texted her explaining that I was busy traveling and working on some computer programs and that's why I hadn't replied to her for so long. I then woke up and received the following message:
conversation*
conversation*
Ever since, she hasn't replied, when she usually replies very quickly (I took around 30mn to reply).
I didn't reply to a girl for about two days and now she seems to be angry, what should I do?
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