The symptom of your stomach feeling jerky is not implantation. Bedding is the union of a fertilized egg with the wall of the uterus in the uterine cavity, which allows the fertilized egg to settle down in the uterine cavity for stable growth and development. During implantation of the fertilized egg, some symptoms may occur such as delayed menstruation, breasts becoming tender, nausea and vomiting, mild abdominal discomfort, and sometimes uterine contractions as well as very small amounts of vaginal bleeding may occur. There are many things that can cause stomach cramping, it can be the abdominal muscle spasm caused by cold or irritation, or it can be the gastrointestinal spasm caused by rapid gastrointestinal peristalsis. You can use a hot towel to compress the stomach, the general symptoms can be relieved, if you continue to have such symptoms, you need to go to the hospital.