I cannot tell you if radiation exposure is the cause of your symptoms. I can tell you that radiation causes injury to the fastest growing cells and your intestines contain some of the fastest growing cells in the body. Temporary damage to your intestines can cause nausea.
The skin also contains fast growing cells and exposure here can cause injury like a sunburn.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.