Without knowing your medical history or taking a look at you, this is a hard question to answer. Many moms-to-be don’t feel great towards the end of pregnancy. Nausea may return, and backaches are very common, due to the change in weight and posture. Diarrhea is less common as a pregnancy symptom, although it can be caused by trying to eat a healthier diet than usual (extra fruits and vegetables, more milk products, etc.), by taking laxatives, or even paradoxically by severe constipation.
If you feel like you are ill, or if you have a fever, pain with urination, decreased appetite, or aren’t able to keep liquids down, call your doctor or midwife right away or go to an emergency room. If these are more chronic problems, discuss them with your primary provider at a convenient time so she can make a full assessment and recommendations.