Hi
Welcome again to the MedHelp forum!
Evening rise in temperature is generally due to anemia, diabetes, hypothyroid states, overwork, stress and fatigue. It is also seen in diseases like tuberculosis.
If your stomach too feels queasy, there is a chance that you have inflammation of the bowels as seen in IBS, colitis or maybe even gluten or lactose intolerance. Discuss this with your doctor and try and get investigated. In all probability it is anemia since you just had a baby. Take care!
Also I just had a baby 3 months ago