My Daughter Is 20 And Has Been Having Horrible Stomach

My daughter is 20 and has been having horrible stomach pains and lower back pain. She can't eat and is hungry has not been able to have a bowel movement although she did have one finally last night and is tired. She had an ectopic pregnancy about 8 months ago and the Dr gave her a pill so she would miscarry. She went through quite a traumatic time
She had an ultrasound this morning and they said she had free fluid in her stomach around her ovaries. What could it be? Is it serious?