Need opnion for my big sister

My oldest sister has had several miscarages and she hasn't had a cycle in over a month she has problems carrying a baby. She was spotting latnight like a light pink color she took two first response pregnancy test both came back negative. She been having lower adominal pains it starts on her right side goes to the middle.and when she is on her feet for too long it circles her lower stomach and goes to her back. She has been feeling nauseous.