Dreaming of a dormitory is often a sign that you are comfortable with your character and are relaxed with your personality as a whole.
You don't beat yourself up about your aspects of yourself that are not desirable to everyone in your life and accept that you have flaws just like everyone else. Essentially you are totally at ease with yourself both good and bad.
On the flipside, it could indicate that you feel bittersweet about your life right now. You dart between feeling like you have accomplished a lot but also very little when you compare yourself to others. The easiest way to explain this mixture of emotions is to compare it moving out of your parent's house and into a dormitory. It feels unrestricted at first- then you find sharing a room with others doesn't give you as much freedom as you'd envisaged.
Dreaming of a dormitory can therefore mean that you need space. You may feel stifled by your living situation. Perhaps the person or people you live with are overprotective of you and are very demanding of your time or maybe you feel you need more room if you currently live in a small flat, house or are renting a room. The two biggest invasions of your space are people (usually a partner) and surroundings so it is likely down to one of these factors.
Another translation might be that you have just made a big decision and you're unsure if it's the right one. You may have decided to move job, house or even start a family and you're not 100% convinced it's the right move for you so you feel trapped as a result.
One final thought is that a dormitory represents the value you place on knowledge. You prefer to be always learning- even if you left school, university or college a long time ago. Perhaps the job you are currently in doesn’t offer any additional training and this is playing against your instincts.
Source: The Complete A-Z Dictionary of Dreams