Dreams can often serve as a reflection of our subconscious thoughts, fears, and experiences. Your dream is rich with symbols and emotions, which can help us gain insights into what you may be processing in your waking life.

1. The Doll: Dolls in dreams can represent childhood, innocence, or aspects of yourself that feel vulnerable. The lifeless, blue-eyed doll that seemed to shake its head at you might symbolize feelings of judgment or shame regarding your own desires or actions, particularly in relation to intimacy and sexuality. The fact that you felt it had an "evil" presence could indicate an internal conflict between your desires and societal or personal beliefs about those desires.
2. Masturbation and Guilt: Your actions in the dream suggest a natural exploration of your sexuality, but the doll's reaction may reflect feelings of guilt or fear associated with this aspect of yourself. This could be a manifestation of past trauma or societal conditioning that makes you feel as though your desires are wrong or taboo.
3. Family and Protection: Your boyfriend represents feelings of safety and attraction, while your family members' presence in the dream may symbolize a desire for support or understanding regarding your fears and experiences. The mention of your cat and the phrase "Dot" could be a sort of comforting presence amidst the chaos, perhaps indicating that you seek familiarity and comfort in your pets or in your relationships.
4. Fear of the Attic: Your fear of the attic and previous nightmares in your bedroom suggest unresolved fears or anxieties lurking in your subconscious. Attics often represent hidden thoughts or memories, so this might point to a need to confront and process these feelings.
5. The Breaking of the Doll: Your act of throwing the doll down the stairs and breaking its head may symbolize a desire to confront and eliminate the negative feelings or energies that you associate with it. This act of destruction could represent a cathartic release of fear and a need to reclaim your power over your fears.
6. Recurring Nightmares: Since you mentioned having frequent nightmares, it's essential to explore what themes recur in these dreams. They may indicate unresolved trauma or fears that need attention. Consider speaking to a therapist or counselor to help process these experiences in a safe environment.
7. "Dot": The word your cat said could symbolize something meaningful from your past or present that you may need to explore further. It might be worth reflecting on any associations you have with that word or sound.

In conclusion, your dream appears to be a complex interplay of your desires, fears, and unresolved trauma. It may be beneficial to engage in practices that promote emotional healing, such as journaling, therapy, or mindfulness, to help you navigate these feelings and gain further clarity.