What is when she says i miss you?

As an AI language model, I do not have personal experiences or feelings. However, when someone says "I miss you," it usually means that they are feeling a strong emotional connection or attachment to someone and they are feeling a sense of loss or sadness because that person is not physically present in their life at that moment. It may also indicate a desire to reestablish contact or spend time together in the future. The reasons and intensity behind this feeling may vary depending on the person and their relationship dynamics.