I just want to ask what cause of execessive menstration and how to cure it?

See a doctor: You should be evaluated for anemia due to excessive blood loss, medical or hormonal conditions such as low thyroid function, and structural conditions including endometriosis or cancer. If this has been going on for a month, as you've stated, then you've waited long enough, by anyone's standards. See a doctor.

Many causes: Local causes from uterus and ovarian problems and then systemic problems like low thyroid hormone level in the body from undersecre. Thyroid ( thyroid gland is influenced by another gland in brain ) called pituritary gland. Pituitary gland when destroyed by less blood supply , cysts, tumors close to it cause low thyroid function .Common ones are uterine, ovarian and thyroid ones.Pl see your gyn.Doc.

Mostly hormonal: This is most often caused by hormonal imbalances. You should see your doctor to have it evaluated and make sure nothing more serious is going on as it can also be caused by benign tumors called fibroids and more rarely by uterine cancers. Most of the time it is hormonal imbalance but a checkup is required to rule out the others and make sure you are getting the proper care.