What could be causing my teeth to be bleeding? they only bleed when i brush them rigorously and there is no toothache or anthing.

Gum disease, : Plaque or calculus (tartar) build up around your teeth can cause inflammation of the gums and thus bleeding. See your dentist for a cleaning.

Gum infection: You definitely could have infected gums (gingivitis). You need to see your dentist for a thorough exam and x-rays. At your age you could be developing bone disease (periodontitis). In either case infection gets into the blood contributing to other health risks such as increased risk of heart attack, stroke diabetes and cancers.

Could be minor: You may well brush often, but do you brush often very well. Just missing an area or being less effective in technique can lead to minor inflammation of your gums. If you then brush hard (rigorously as you put it) may be more irritant than cleansing and hence the bleeding. Review with dentist or hygienist and adjust your techniques of brushing and flossing. Good luck!