Hello, Being lost in your own thoughts or day dreaming can be a normative day to day experience for many people, and rather be a healthy coping mechanism to many of these. However if the day to day functioning becomes affected by the frequency, intensity, or by inability to shift focus to real time world from the fictional or dream world it may signify a mental health disorder. If the distress due to such phenomenon is significant and the individual seems to lose control over these, then also it may be a marker of significant health problems. Such maladaptive day dreaming may be a part of normative thinking, autistic features, depression, Obsessive compulsive disorder, generalized anxiety disorder, some personality clusters, or an emerging disorder called Maladaptive day dreaming disorder. However before concluding you must seek a consultation with a psychiatrist near you for comprehensive assessment. A detailed assessment can help you understand the underlying reason behind your symptoms, and thereafter a management plan can be decided. However be assured that your condition can be helped and with appropriate management you can get back to your health.. Hope this helps you. Best wishes for your health and future..