im addicted to junk food

Take a step back and a deep breath.
Make sure your MFP profile is complete and it gives you a calorie estimate (shoot for a very moderate weight loss) then try logging what you eat as accurately as you can. That way you can accurately visualize what your doing and hopefully it will inspire you to action.
I'm not sure where you stand on faith, but LONG ago I had success with Overeaters Anonymous (www.oa.org) which is based on the 12 step program.
Good luck sweetheart and much love to you.

I have the same problem as you, but I tend not to tell anyone about it

I have struggled with this a lot myself. I will get a bag of something and say I will just eat a little bit and before long, I have eaten it all. What has helped me so far (and this is lifestyle ideas, not to replace therapy if you feel you need it) is to focus on:

-why I eat that much junk food (for me, anxiety and certain activities trigger it- for example, I will be at work and not eat for a long time when I focus on my job but if I put on the TV at home, I find I want to snack badly within minutes, it's almost weirdly Pavlovian).
-I also try to find ways to incorporate healthier options that I really like into my snacking. I love sweet things, so I buy frozen berries, grapes, strawberries, etc and have them on hand when the strong urge for sweet comes on. When I really want to have dessert options, I will occasionally by lite whipped cream to mix them in with.
-I have been focusing on snacks that also fill me up more (right now, I focus on higher protein snacks like low fat string cheese or Greek yogurt). Fiber from veggies helps too (baby carrots help when I get the munchies).
-Logging it all, good or bad is important. It helped me realize than my "bad" times are between 4-6pm, when I am getting off work and I am tired and hungry and am tempted to stop and grab a little something convenient. I have added an afternoon snack (string cheese- I love it) to help me make it through to when I can cook dinner.

For my issues (maybe not the same as yours), knowing what behaviors trigger my desire to eat those foods has helped. I have started working out more (not so I can eat back calories, but so I don't just go straight home and binge watch Netflix) and cooking at home more (even things like burgers and fries made at home are healthier than McD's- I love turkey burgers and oven fries with EVOO and rosemary) and they also take up time so I am not sitting around being bored and anxious. I have tasks to complete that require my attention and stop me from eating junk food. I also love to garden and I am looking forward to adding more of that now that the season is right.

Just remember you are not alone, that there are support groups, etc. for help, try and get to the root of why you like those foods and when you eat them (logging really helps with this), and stay positive. Good luck on your journey!