It is definitely important for you to work on your diet if it is horrible... Keep running though as that will help...
Read up on building a healthier food plan at the right calorie level... To get you started - cut out junk food and takeaways and make sure that you are drinking plenty of water. Also try to eat more fruit and veg - either raw or cooked in a healthy way and swap food for low calorie equivalent (fry light for cooking, skimmed milk, low fat dairy, granulated sweetener).