How come if i skip breakfast, i feel faint when i'm standing?

Many potential cause: The most common cause of lightheadedness is simply a lack of fuel in the brain (oxygen + glucose + triglycerides) in one form or other. I'm not sure for you which is the problem - low blood pressure (i.e. Not enough blood), low blood sugar (not enough glucose) or low brain triglycerides (the preferred fuel of the brain), but it is probably one of these. Eat breakfast, and stop worrying about it.

Sugar?: This could be an early sugar problem. Check with your doctor.

Food is good: In order for you to be able to go from a sitting position to walk, your body needs to make certain adjustments. Once you stand, your blood pressure has to increase. If you are dehydrated, then the body cannot increase the blood pressure and cannot pump enough blood to your brain, thus the feeling of fainting. Also, you have to be careful of low blood sugar in the morning. So, eat breakfast!