I have recurring dreams of people breaking in as well. During childhood I was always scared of burglars breaking into my house during the night and quite naturally as an adult I still am to some extent. Every night before I go to sleep I lock my door to prevent this and in the back of my mind this concern is always there even if it’s only subtle. If I’m ever woken in the night by an unexplainable noise my first thought is always “someones breaking in!” even though it never is. I think this heightened vigilance in the night whilst I sleep may be the reason why I have recurring break in dreams and I think it may be the same for many others.