While I don't really agree with the tone some people are taking in this conversation, I do think that their message of "slow down" is an important one. AC, you're very new at your current institution, and it's hard to know how much of your discomfort is just a result of not being settled in yet. I know I'm new to my program and I'm profoundly uncomfortable and often feel that if I had gone somewhere else it might be better, and I don't think it's because the program's structure is wrong for me - I'm just very unsettled-in. Also, it's very important to consider how what you do will look to others. Imagine this is a job on your resume: would it look good to quit after a few months? No!!
My advice would be to wait AT LEAST a year. You need to be sure that you truly can't work with this program, and you need to assure other people that you took the time to give it a chance. Ideally, do get that MS; you won't have to "start all over" afterwards, time-wise, for your PhD, because you'll have gained so much research experience you'll be much more efficient in your dissertation work.
Something that I feel hasn't been said yet and should have been is this: if you give this program a real chance and it doesn't work, get that MS and get out. Do not get a PhD in a field you don't like or with people you don't respect. Your work will not be your best, and your PhD will not reflect what you really want to do. Your dissertation work is what will get you noticed, will brand you, and will get you a job and a career - or not. So, first, give yourself the chance to really evaluate this program and give yourself a reputation for rational, deliberate decision-making. Then, whatever you decide, get a PhD that reflects what you want to do.