for an example I went and bought two sandwiches from McDonald. After eating I went to Wal-Mart to get food for an event. I went shopping for an hour and as soon as I got out I wanted to eat again. Why do I have these weird urges to eat when I can tell that I'm already full awhile ago.
Tank, I have the same thing as you do. I did not know why I kept on getting hungry right after I just got really full. So, I asked my mom. She said that it was because I was going through a lot of puperty and growth hormones. She said that I am at an age where that happens. So, you probably are not the only one going through this.
Maybe you are just thirsty which can feel like hungry. Also maybe you're eating alot of junk, like stuff from McDonalds which doesn't last long at all for keeping you full.
Maybe you're not getting enough vitamins and nutrients from other kinds of food, try eating different things and see what makes you stay full longer. I recommend whole grain bread and cheese, buttered rice, fruit, fresh vegetables with dressing, refried beans, tuna fish, almonds, yogurt, milk, eggs. Avoid too much sugar.
Discipline. That's the most important thing you have to thing about. When you're going out and you have something to buy don't buy exes for your self. Buy something that's important. When your full stop eating, drink plenty of water. The urges to eat will lose when you always think that you will become bigger and bigger.