i would quit, if i were you, because you say, you really want to quit. and if you've thought about it for 2 weeks, than its not just an impulse, but a true feeling.
i too did not want to quit because of fear of dissapointing everyone. but a phd is hard enough as it is, without doing it for other people.
trust me, in hindsight, i wish i had quit after my first year. i just didnt have the courage to do so.
do what you REALLY want to do, and dont even think about what other people will think. its you that will be working hard.
my advice, do what you really want to do. the whole world is out there!