Wife was sitting on couch eating. all of a sudden started feeling dizzy. resting now. she breast feeds and doesn't get a lot of sleep some nights.

See MD ASAP: Your wife needs an immediate full history exam and lab tests. Studies show that pregnancy causes women to shed more iron than most and women sometimes develop anemia. Her vital signs need to be assessed. Women also develop postpartum thyroiditis which can cause some of these symptoms. Differential is large and arrhythmia and vertigo also would be considered based on thorough history. See MD.