I used to be a comfortably social person meeting new people frequently However for about a year now I have inexplainably became more quiet and awkward during conversation How could this be?

Unexplained changes in personality can be due to life changes such as death of a partner, moving into new living situations, loss or change of job, finishing a "life project" such as a degree and feeling awkward about moving on, and so forth.

They can also be a sign of a developing emotional dysfunction, or physical issues such as developing diabetes, etc.

Clearly this is causing you a lot of concern. We suggest a complete physical to rule out any medical problems. At that point, if you do not feel more confident, a few visits to a therapist might be in order.