Muscle Core X won't do any good. I don't know what's in it, and it doesn't matter. It could be anabolic steroids mixed with cocaine and it wouldn't make much of a difference for you, because what you need cannot be distilled into a powder.
For someone just starting to work out, no supplement will do much good. Powders and shakes are well-advertised and quite profitable for the people selling them, but are indistinguishable from useless for someone just starting to get in shape. Save your money.
Stop putting your hopes into consumer products. They will not save you. The only thing that can get you in shape is hard work, performed consistently, without excuses. The universe doesn't care that you work at a camp. The laws of biology and physics will cut you no breaks. You must overcome these obstacles.
One month to get fit
You can get in better (but not great) shape in a month--if you rearrange your entire life. But even the perfect workout schedule, Herculean effort, and optimal diet will only have moderate results. One month is simply not that much time.
But you could change everything you do for one month and make a dent. Go to sleep early every night, wake up early to run a mile every morning, eat only real food with plenty of animal protein and good fats. Start doing sets of 20 barbell squats three times a week, keeping in mind that using imperfect form with heavy weight will cause injury but using only light weight will not produce change. Do fifty chin-ups each day, split up however you have to, and pray you don't get elbow inflammation. Learn to deadlift and bench. Run two sprint or high-intensity interval training workouts a week. Miss no workouts. Skip no exercises. Get perfect sleep, avoid all stress, get plenty of sunshine but no sunburn, and eat a perfect diet. (Remember that there are at least a dozen broad definitions of the perfect diet and they all contradict each other and the right choice depends on a thousand individually-nuanced factors.)
If you do all of that perfectly, no exceptions, no injuries, no mistakes, then you'll be in somewhat better shape in a month. You won't be "in shape", it won't be a stunning, head-turning difference, but it'll be a modest improvement.
That plan is conceivably possible. But more likely you won't or can't restructure your life so drastically, or something will go wrong. Therefore you should define your goals, research a workout program that fits your goals, and ease into it slowly so you don't get injured. You won't stun your ex, but that's a silly goal anyway. Better to work out for you, to become the awesomest Matt you can be, than to chase someone else's fickle affections. Take the long view.
Ross Enamait uses an example of someone who dramatically changed his body over the course of a year:
Significant changes in body composition do not happen overnight.... Quick fixes are a marketing creation. They don’t exist in the real world.
The best time to start may have been ten years ago, but the second-best time to start is today.