there are many types of dissociative disorders for example Dissociative fugue, dissociative amnesia, depersonalization disorder, and Dissociative Identity Disorder, DDNOS (dissociative disorder not otherwise specified) here's some info from NAMI (national Allaince for mental illness) ............

Dissociative disorders are so-called because they are marked by a dissociation from or interruption of a person's fundamental aspects of waking consciousness (such as one's personal identity, one's personal history, etc.). Dissociative disorders come in many forms, the most famous of which is dissociative identity disorder (formerly known as multiple personality disorder). All of the dissociative disorders are thought to stem from trauma experienced by the individual with this disorder. The dissociative aspect is thought to be a coping mechanism -- the person literally dissociates himself from a situation or experience too traumatic to integrate with his conscious self. Symptoms of these disorders, or even one or more of the disorders themselves, are also seen in a number of other mental illnesses, including post-traumatic stress disorder, panic disorder, and obsessive compulsive disorder.

Dissociative amnesia: This disorder is characterized by a blocking out of critical personal information, usually of a traumatic or stressful nature. Dissociative amnesia, unlike other types of amnesia, does not result from other medical trauma (e.g. a blow to the head). Dissociative amnesia has several subtypes:

Localized amnesia is present in an individual who has no memory of specific events that took place, usually traumatic. The loss of memory is localized with a specific window of time. For example, a survivor of a car wreck who has no memory of the experience until two days later is experiencing localized amnesia.
Selective amnesia happens when a person can recall only small parts of events that took place in a defined period of time. For example, an abuse victim may recall only some parts of the series of events around the abuse.
Generalized amnesia is diagnosed when a person's amnesia encompasses his or her entire life.
Systematized amnesia is characterized by a loss of memory for a specific category of information. A person with this disorder might, for example, be missing all memories about one specific family member.
Dissociative fugue is a rare disorder. An individual with dissociative fugue suddenly and unexpectedly takes physical leave of his or her surroundings and sets off on a journey of some kind. These journeys can last hours, or even several days or months. Individuals experiencing a dissociative fugue have traveled over thousands of miles. An individual in a fugue state is unaware of or confused about his identity, and in some cases will assume a new identity (although this is the exception).

Dissociative identity disorder (DID), which has been known as multiple personality disorder, is the most famous of the dissociative disorders. An individual suffering from DID has more than one distinct identity or personality state that surfaces in the individual on a recurring basis. This disorder is also marked by differences in memory which vary with the individual's "alters," or other personalities. For more information on this, see the NAMI factsheet on dissociative identity disorder.

Depersonalization disorder is marked by a feeling of detachment or distance from one's own experience, body, or self. These feelings of depersonalization are recurrent. Of the dissociative disorders, depersonalization is the one most easily identified with by the general public; one can easily relate to feeling as they in a dream, or being "spaced out." Feeling out of control of one's actions and movements is something that people describe when intoxicated. An individual with depersonalization disorder has this experience so frequently and so severely that it interrupts his or her functioning and experience. A person's experience with depersonalization can be so severe that he or she believes the external world is unreal or distorted.

Treatment
Since dissociative disorders seem to be triggered as a response to trauma or abuse, treatment for individuals with such a disorder may stress psychotherapy, although a combination of psychopharmacological and psychosocial treatments is often used. Many of the symptoms of dissociative disorders occur with other disorders, such as anxiety and depression, and can be controlled by the same drugs used to treat those disorders. A person in treatment for a dissociative disorder might benefit from antidepressants or antianxiety medication.

........ If you want to know specifically which type of disorder that you have you can ask your therapist to refer you to a psychiatrist or psychologist to take a comprehensive Psychological Evaluation with suplimental tests for Dissociative Disorders.

medication cant fix DID but antidepressants and so on can help with the anxiety and panic that you feel when you realize you have lost time

as for what specifically is going on with you only a professional can tell you that. it could be a disorder or since all people naturally have some dissociative abilities it could also be normal if you are under stress for people do at times normally forget things that they say and do if they are under stress or just having a very busy day.

Some medical problems also cause forgetfulness and getting lost and so on so for example a recent fall in which the person hit their head, tumors, naatural aging process, alzeimers and so on and again only your family physician can rule those things out.

Since you are in therapy your therapist is your best option for finding out what is going on specifically for you.

hang in there