lump in groin area year after BC

I found a lump in my groin area and in a week has gotten bigger but no pain at all. Do I need to worry the cancer has come back.  Second question I started my period back in August after 6months of not having it due to chemo. Did mastectomy, stomach is severley bloated past 2 months found cyst on right ovary.  BRAC1 positive, back pain, nausea/vomiting, constipation could it be pregagnant systems or ovarian cancer symptoms? How do I know its pregnancy with no breasts?