Maybe you are in a hurry to do something, so he is particularly surprised and has been paying attention to whether you can reply to the message. I can see that this girl is also in a hurry. I think she is closer to you.
You can reply to her like this: because I want to chat with you, because I haven't seen you for several days. Then I just want to talk to you. I feel flustered when I don't see you, and I always feel that I don't know what to do, but I feel very practical as long as I chat with you.
If you have something, just tell him directly and tell the truth.