Imaginary friends at 18?

I'm 18 and I lead a very stressful and secluded life (I'm a caregiver for my mom and aunt, who are disabled and/or housebound). I don't have any friends. None. Literally. None of my family speaks to us and my dad's only interested in being a father when he feels like calling me 3 or 4 times a year for 5 minutes. I was homeschooled so I don't have any friends from school. My aunt is paranoid and narcissistic but refuses to get professional help. My mom goes through mood swings. So for several years (probably since I was 11), I've had imaginary friends. I know they're not real and I don't speak to them out loud and they don't control my actions or anything like that. I never had imaginary friends as a child. It just makes me feel better when I get upset or stressed to imagine someone being nice to, me. Does it make me abnormal or crazy?