Unless you give more details we can only guess that the person is in Vietnam, is tired and confused for many reasons, depending on why he/she is in Vietnam in the first place.

It means that the person is in Vietnam. He/She has probably been there a long time, so they are feeling both tired and confused. Maybe it's about the Vietnam War. If so, that person is a soldier who is confused about the reason they are in Vietnam, and tired of all the pointless fighting.