I too have the same problem and I am also trying to lose weight. First and foremost is changing your eating habits. Eat healthier, have your 3 meals and snack on healthy snacks like almonds, raw veggies, fruits, yogurt... every 2 to 3 hours to keep your metabolism up. Try keeping a food diary, I suggest using the app My Fitness Pal to track calories and exercise. Start off with easier exercise programs. Try an hour a day. Cardio will help get your heart rate up but don't over do it. Try videos like Zumba or Jillian Michaels 30 day shred. It will be hard at first but I promise it will be worth it. Also remember that you are beautiful at any weight and you should accept your body for what it is. Don't do it to lose weight do it to be healthy. If you cheat, its okay. Pick back up where you left off. Cheating on a diet is normal and doesn't mean you have to give up. Good luck hun and if you need anything else let me know and I can hopefully help!
If you're able to go to a gym (Planet Fitness is only $10 per month), try that. Good atmosphere, don't be shy, people at gyms aren't jerks like most people starting out think. If you can't make it there, start out walking. I walk at a pace that gets me sweating and go for 30 to 45 minutes.
Follow the calories they give you on here also. The 500 calories alone you can cut out from your daily intake will lead up to losing 1 pound per week. Another 500 from exercising will be 2 per week. Slower is better. Not what you want to hear, but it gives you time to adjust and learn to eat right. You'll be less likely to gain it back.
Read "the Paleo Diet". It's a great way to lose weight and feel great.