I constantly find blood on my toothbrush while I am brushing my teeth in the morning.

Just a little, but quite often.

Am I lack of certain Vitamins?

Sounds more like gingivitis or gum disease. Go see a dentist and have your teeth cleaned and ask about preventative or curative rinses, toothpastes, etc. Make sure you brush, floss, and use mouthwash several times a day, and after each meal. Brush in small circles, and don't push way hard, that's not good either. Use a firm toothbrush, but not a "hard" toothbrush. Make sure you use fluoride toothpaste.

It could be from sores or abrasions in your mouth, or simple gum irritation because of brushing too hard. Use a saltwater rinse to aid in healing and to toughen up the inside of your mouth. Consider switching to an electric toothbrush, and pay attention to how hard you are pressing when using it. There's a new one on the market that alerts you if you press to hard.

Have you been bleaching your teeth? If so, and the bleach got onto your gums or the roof of your mouth, it could cause sort of like a chemical burn, which would cause bleeding. If this is the case, stop bleaching and again, rinse with saltwater to promote healing.

Make sure you are flossing before bed; if food particles have been rotting between your teeth all night it could cause gum irritation. Also make sure you are flossing CORRECTLY, many people do it wrong. ADHA - Proper Flossing (http://www.adha.org/oralhealth/flossing.htm)

Make sure you are drinking lots of water, if you are dehydrated you can have oral problems as well.