Whenever we have alternating identities in a dream, it means that we are seeing two sides of whatever person or object in the dream is being represented. In your case, you see the nice normal side of your boyfriend, in which he treats you like a princess, but you also see him represented as a rabbit. When he is a rabbit, he is mean and requires a lot of care. He also betrays your friendship (calls you names) behind your back.
The representation of your boyfriend as a rabbit is significant. Rabbits in dreams are symbols of fertility. (The Easter Bunny, in fact, is a famous fertility symbol. He comes in the spring, passing out eggs to children.) Accordingly, your dream is representing your fears that your boyfriend is sexually active when he is away from you—“breeding like a rabbit”—and passing out his “eggs” to other women.
It is significant that, in the dream, you spend a great deal of time trying to control him when he is a rabbit. As in real life, you worry whether he is faithful when he is away from you (out of your control). Your dream shows that you have your suspicions about your boyfriend, and that you are devoting a good deal of mental and emotional energy to worrying about him.
The second part of your dream continues the theme of fertility. When you go to visit your newly married best friend, she suddenly is carrying a 20-week-old baby. The baby in the dream represents her new status as a married woman, but it also carries literal associations. Now that your best friend is married, she will soon be starting a family of her own, with real babies on the way.
It is natural when a close friend moves on to the next stage of his or her life that we compare ourselves to them. Accordingly, your best friend’s recent marriage most likely has caused you to wonder about your own time line for marriage. Is your relationship with your boyfriend headed in the right direction? Will he be “the one”?
The added pressure you feel to catch up with the “newly married crowd” almost certainly is the cause of this “out-of-control rabbit” dream. What’s the meaning? Dreams of betrayal are reflections of our own insecurities—and should not be considered precognitive. It’s time to give your boyfriend a carrot for good behavior, and to let go of those nagging insecurities!