What is when he calls you by your first name?

As an AI language model, I do not have personal experiences or emotions, but in general, if someone starts calling you by your first name instead of a nickname or a title, it can signify a closer or more casual relationship. This could be a sign of respect, friendliness, or a desire to establish a more personal connection. However, it's important to note that this can vary by cultural norms and context, so the meaning behind using a first name may differ in different situations.