Can't stop fantasizing.

Two weeks of no PMO make you crave for fantasies. Your brain has no source of pictures, so it's like, well, "panicking". I think that you should focus on two things:
-not thinking too much about these fantasies, because they're going to get weaker and weaker - be conscious that it's just another step in the process and you MUST pass through it to get better,
-doing something to keep yourself away from the fantasies. I don't know what works in your case, so I'll just count some random things that me and others talk about in such situations: cold showers, working out, meeting others, praying and going to church, taking up some hobby, giving more effort into your job/school etc.

Another thing is the issue with your girfriend and your aunt.
Your girlfriend: I don't know how close you are, so it's hard for me to give any specific advice. One thing that applies to all women is that they are not objects. Fantasising creates a "doll" of your girlfriend in your mind. It's not really her, even though she looks just like her. If you love her, spend time with her, but appreciate her as an individual, as a person.
Your aunt: porn makes our brain messy, and in a number of cases even leads straight men to gay porn. Don't be surprised that you have incest-like thoughts. Think about your future. You have one life, and in your individual life, you'll be a part of your family till you die. With that in mind, imagine doing something stupid because of your addiction. Risking your family relations for a fantasy isn't a good idea, right? Also, as in the case of your girlfriend, your aunt is a person, not an object. Try to respect that.

You're two weeks into reboot. Believe me, your fantasies are going to fade away if you give it time. Just don't be passive.
Stay strong, because you're already doing great.