Tissue and large blood clots in period with painful cramps and nausea?

Possible Miscarriage: Can be due to miscarriage If symptoms are bad you might need to go to ER for treatment

Vaginal bleed: Important to urgently know your pregnancy status. Take a test now and if positive seek urgent attention. Otherwise may be infection or menorrhagia (heavy period) but safest to see a doctor for an examination

Blood clots in perio: Agree with ruling out pregnancy and seeing a physician to have a proper exam since fibroids might also be a reason for excessive bleeding.