When Valerie leaves her house, she experiences unwelcome thoughts that make her nervous, so she engages in repetitive behaviors that make her feel calmer so she can get into her car. Based on this, Valerie is most likely to be diagnosed with:

obsessive-compulsive disorder

Explanation:

Obsessive-compulsive disorder is a psychological disorder that causes a person to repeatedly perform a task or have unwanted thoughts or sensations. A person suffering from OCD may perform several compulsive tasks such as checking the lock of the door, washing their hands, making everything lie in symmetry, or they may have obsessive thoughts about good or bad things. In the given case while leaving her house Valerie is obsessing over negative thoughts as well as is conducting compulsive repetitive behavior which is an example of obsessive-compulsive disorder.