The Shrink Is In (2001) on Netflix

Samantha's a travel writer who's dumped by her boyfriend just as she's about to leave. As a result she suffers a breakdown and pulls the emergency exit cord on the plane. She is arrested and ordered into therapy. She becomes utterly neurotic and starts to eavesdrop on her neighbor who is going through a rough time with his girlfriend. When her therapist suffers a breakdown of her own, Samantha takes her to the hospital and the staff tell Samantha that someone has to tell the therapist's patients that she'll be unavailable. Since the therapist has no secretary Samantha does it. Then a guy comes looking for the doc; it's her neighbor. When he assumes Sam is the doctor, he starts talking and Samantha hoping to get him to dump his girlfriend, doesn't correct him. Alnother guy, magazine salesman comes looking for the doctor and Samantha has to treat him too.