"I don't know why."

In the morning of today before arriving at uni, A texted me saying "morning", "how are you", "its snowin here" and of course I texted her back.

Before the lecture started, I was waiting outside the lecture room with E. A comes along and we say Hi to each other. But when it was almost time to go in, A just went off to the lecture room by herself. I was thinking, "Wow what a friend to not go with other friends to the lecture! Especially when she texted me just this morning like all is well!". E noticed too. E asked me why me and A don't sit next to each other anymore, and basically told her the truth, "I don't know why.".

I did nothing but just a miss a couple of useless forward text messages and didn't reply to them. When I texted her saying: "Soz, didn't text you back. Been busy doing cwk" and she goes: "dont remember txting u, neway its kool". What? How the eck do you not know when you text someone? Or is that a sign for me to leave her alone?