Your Text Sounds Angry
One of the first things they teach you in business communications class is to be wary of what words you use when texting others. This is due to the fact that other people may not perceive your message in the way you intended to deliver it. The recipient may use their own feelings and judgments in determining what you really meant when all you said was just Yes.
That said, there’s no possible way the OP could’ve misconstrued the meaning of the Yes in this text. How does her one-worded answer make her sound angry? Well, yeah, we sort of get it, especially if she used single-worded answers in anger in the past.