How do you resist junk food?

today is just one day. You haven't failed at anything if you get right back at it tomorrow

Yes, this.
Pick yourself up, dust yourself off, and do better tomorrow.
Next time there's a temptation, don't go overboard. Don't deny yourself either, just have _some_.
I live alone, so it's easier for me to tell myself "no" at the grocery store than to have some favorite temptation sitting around here calling to me.

Maybe you could get a bag of dark chocolate chips (I like Girardelli 70%) & have a serving. (Yes, count out however many chips they say are in a serving into a bowl, put away the bag, and sit down to pay attention to enjoying your chocolate very slowly; let it melt on your tongue & don't eat the next chip until that one is swallowed.)

"Most weight loss occurs because of decreased caloric intake.
However, evidence shows the only way to maintain weight loss is to be engaged in regular physical activity."
http://www.cdc.gov/healthyweight/physical_activity/index.html

I always tell him not to leave chocolate anywhere in my sight because I'll demolish it all but nevertheless it's alwyas in the same place and he always complains when there's none left and that they're bad for me!

Why does he want to sabotage your weight loss?

Is your goal weight healthy for you?
Here's a BMI chart: http://www.shapeup.org/bmi/bmi6.pdf
You want to be in the green range, preferably near the middle.

Once you have a healthy goal weight, this calculator will tell you not only your BMI, but how many servings of various foods to eat to maintain that weight. If you enter your healthy goal weight, this will help you plan your food intake.
https://www.bcm.edu/research/centers/childrens-nutrition-research-center/healthyeatingcalculator/eatingCal.html

I wish I looked like I did 4 months ago. I NEED to lose those 15lbs.

Your ticker says 10 lb.
Either way, that's not much to lose, so it's going to happen slowly.
(And if you're trying to be underweight, it's going to be even harder, and don't do it.)
If you see 0.5 lb per week, be happy.
To do that, you need to be 250 cal under what you're eating to maintain your current weight.
That's not much.
If you're aiming for (as an example) 140 lb, eat 1400 cal per day. That's TOTAL, not net. Ignore net, ignore exercise.

When I started skipping breakfast and making my first meal of the day no earlier than 10 am, my cravings for "bad" foods became blunted. Working through your morning "hunger" seems to reset something in your brain.

Bad advice.
Eating breakfast is associated with lower body weight,
and eating a large breakfast is associated with more loss of weight.

"Breakfast is associated with lower body weight ... "
http://www.ncbi.nlm.nih.gov/pubmed/24898236

This study compared eating a small breakfast, medium lunch, and large dinner, [200, 500, 700 cal]
with eating a large breakfast, medium lunch, and small dinner [700, 500, 200 cal].
"The [large breakfast] group showed greater weight loss and waist circumference reduction ... fasting glucose, insulin [&] triglycerides ... decreased significantly to a greater extent in the [large breakfast] group."
In addition, hunger was less and satiety was greater.
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/23512957
Full text:
http://genetics.doctorsonly.co.il/wp-content/uploads/2013/07/Jakubowicz-at-al-Obesity-2013-oby20460.pdf

"subjects assigned to high caloric intake during breakfast lost significantly more weight than those assigned to high caloric intake during the dinner"
Abstract: http://www.ncbi.nlm.nih.gov/pubmed/24467926
Full text: http://www.tradewindsports.net/wp-content/uploads/2014/03/Nutrient-Timing-and-Obesity-2014.pdf

"data suggest that a low-calorie Mediterranean diet with a higher amount of calories in the first part of the day could establish a greater reduction in fat mass and improved insulin sensitivity than a typical daily diet."
http://www.ncbi.nlm.nih.gov/pubmed/24809437

OP implied she lives with her parents. A lot of you are saying "Just don't buy any treats!" without acknowledging that there are other people bringing the stuff into the house. I live with my mom and am in the same situation. You're living with someone, if they want to buy chocolate they'll buy it. (That's not sabotage by the way, despite what some might claim.) So willpower is the key, OP. You HAVE TO work on that. The more you do, the stronger it'll get.

So here are a couple of tips other than "Don't buy it!" First, if I'm thinking of eating an unplanned treat, I drink a tall glass of water and make myself wait 5 minutes. Then 5 more minutes. Then 5 more. Etc. Secondly, I pre-log every day so I have an idea of how things will fit into my day. That makes it easier to resist, since I have a plan. Third, I'm not above making up songs that I sing to myself-- the words are usually "I'm not hungry, I don't need to eat, blah blah blah."

Hope that helps!

Fellow chocolate lover-- to feed my cravings I go to Whole Foods (or a similar type place) and get half a pound of dark chocolate covered cranberries or almonds. I divide them equally into 7 days. I allow myself one a day. If I exceed this and eat all in one day, for example, none til next week. It's all about discipline. I never tell myself no, just moderate what I allow. It took TIME to get to this place. About a month. So if you bite it, write it! Also pre-packing my lunches for work the night before is a life saver! Feel free to send me a friend request! you can do it!

For years and years, you have been training your body to expect little treats. After you have each one, there is a slump. You feel tired and want another little treat.

This is something that will take you a long time to unlearn. But if you understand you only want the chocolates because your body wants a little artificial high, you can see the chocolate as a sort of trick that you play on your body.

You need food to live. You don't need highs. If you'd never started eating chocolate, you never would have needed it.

That, for me, is the reason I don't really eat chocolate anymore. I still get tricked sometimes, but it's not the end of the world. I just move on and start again the next day.