I might love my best friend?

Me and Tori have been best friends since I was 14 [I'm 19, she's 18]. We never dated, we've kissed before, and held hands, slept in the same bed [but didn't do anything], but nothing more. When I was 16, I got my ex pregnant, and right after my son was born, my ex abandoned him so I took full custody. My son, Riley, loves Tori, he even calls her Mom sometimes. She is at my condo almost everyday and she is going to become my roommate soon, and I constantly find myself daydreaming about her being my wife while she is playing with my son. I've even daydreamed about having kids with her. I am in a relationship though with Dustin [yes, I'm biual, please no offensive comments] me and him have been dating on and off for over a year. And we are on the verge of breaking up again and I think I'm done with him this time. Well, Tori just became single, though she is going on dates with this guy I used to work with -.- but everyday when she comes over, I just feel stronger for her. She's seriously perfect, she's beautiful beyond belief, my son loves her, I think I love her, we know each other inside and out, I don't know what to do. I don't know how she feels, I don't know if I'm right or wrong by feeling this way for her. I'm so confused. What should I do?