Hi. This problem happens with so many girls and not just you. Many girls feel lonely and they start daydreaming. We can solve easily when you actually meet a psychologist once. This is not a disorder but the sadness and loneliness you feel more. In your case, you may have not achieved many things in ur life even on small things. This slowly leads to daydreaming.  If ur not able to cope up with life challenging issues or with ur friendships u tend to get more disappointments. Only dreams teach us to think future in positiveness. But you should be able to accept the reality and work according to dreams. Simply dreaming is useless. To make yourself more confident or come out of Ur loneliness you can visit a psychologist nearby or have a online consultation. We can easily solve but don't prolong this condition. Otherwise u may develop more issues like laziness, lethargicness ,  too much of crying, becoming weak emotionally etc.