Thank you for writing so openly and courageously about your situation. I’m so glad that your son has such a loving and supportive parent! This is not an easy situation to be in. As you said, your son may be gay, or he may not be. Gender expression and identity (as well as masculinity or femininity) are aspects of a person that are separate and distinct from their sexual orientation. Your fear of bullying is a legitimate one. Interests and behaviors that are perceived as feminine in boys are often frowned upon by others, but thankfully, this does seem to be slowly changing in society.
I understand your temptation to discourage the behavior that may lead to bullying in an effort to protect your son, but remember that trying to change what he does will not change what he likes or who he is. And as you probably realize, these interests may not be a phase. As wonderful as your intentions would be in trying to change how he acts and what interests he pursues, the message that he will hear is that he is not OK the way he is. Instead, I would urge you to have honest discussions with your son about bullying and how to deal with it, and the fact that some people don’t yet understand that boys can like pink too, and that it’s OK. Some girls like sports while some boys like ballet. Some girls play football and some boys sing in musicals. Some girls play with trucks and some boys play with dolls. Perhaps there is a school counselor, administrator or teacher you can address the bullying issue with. A great resource for addressing bullying in schools is GLSEN (www.glsen.org).
To address your concern about depression: If you start to see his behavior change, if he becomes persistently sad or withdrawn from you or others, or if you see changes in his eating and sleeping patterns (too much or too little of either), I would urge you to seek the help of a professional counselor who is affirming of all identities right away. Your unconditional love and support is the greatest protection that you can provide to your son. Just keep letting him know that he is wonderful just the way he is, and that you are always there for him! Here is a great resource that may be of interest to you. http://raisingmyrainbow.com/the-book/