Hi i experience irregular vaginal bleeding, i have been bleeding for 3 weeks now. ?

Needs evaluation: More questions need answering: could you have been pregnant and this is a miscarriage? Using any form of contraception? It is not especially unusual for women, especially younger women, to have irregular bleeding as a result of fluctuations in various hormone levels that impact cells lining the uterus. Regulating hormones with The Pill often helps. But more serious causes also need excluding.