I have answered this question many times about dreams. From the psychological point of view, dreams are a normal physiological and psychological phenomenon. As for their contents, some things have no scientific basis. The content of dreams has neither scientific basis nor guiding and predicting significance. Don't take dreams too seriously.
Everyone says "thinking day and night", which means that if a person takes one thing too seriously, he will dream, but it is not reality. You may care too much about your boyfriend, so that's why. Don't worry, it's just a dream!