Presence of clots (as described by you piece of vagina) with 9 days menstrual flow is Menorrhagia(excessive bleeding). This would require thorough gynecological examination. Would advise you to visit a Gynecologist. And white discharge with backache
is suggestive of fungal vagina infection. Anti fungal drugs oral and local vagina antifungal creams/pessaries would help.
Do get back to me for additional information. Would be glad to assist you.
Dr. T. Shobha