I have prepared my case study, but uncertain how to word my diagnosis.

My differential diagnosis are:(1) Somatic Symptom disorder, (2) Illness anxiety Disorder, and (3) Generalized Anxiety Disorder. I am attaching the case study. I chose Somatic Symptom Disorder, but uncertain how to add specifiers at the end.( somatic symptom disorder, persistent severe ?) I am attaching a case study synopsis . Please advise. Thank you!

HISTORY OF CHIEF COMPLAINT: The patient first presented to her primary care provider two (2) years ago with symptoms of headache, difficulty sleeping, and light-headedness. She cried during her first office visit when she told her doctor that she was worried that she had a brain tumor. She was evaluated by her PCP and a neurologist. She had magnetic resonance imaging (MRI) of brain with normal result. She takes ibuprofen PRN for head-ache approximately once per week.She reports symptoms of apprehension, fear of dying, fear of having a serious medical illness, insomnia, tachycardia, light-headedness, fears of her daughter or husband getting ill or injured, chest tightness, nausea, and loss of appetite. She has had increasing attacks. Triggers for her attacks include recurrent thoughts that she has a major medical illness, when her daughter or husband is ill, and flying on airplanes. She states, "I have hypochondrias." Her symptoms are heightened in September when her daughter returns to school and is "around other kids' germs." She reports no symptoms at work and feeling less stressed when she is occupied with activities such as working, spending time with her family, and at yoga class. She has no difficulties at work or in attending to her activities of daily living. She has been taking clonazepam 0.5 mg one tablet QAM for the past 6 months prescribed by her PCP. She does not know what is wrong with the doctors that they cannot find anything wrong and she is having all these physical problems.

PAST PSYCHIATRIC HISTORY: She saw a therapist while in college for similar symptoms related to her parents' divorce and her college workload. She reports no history of depression symptoms. No rituals or compulsive behaviors. She was prescribed paroxetine for while in college. She stopped taking paroxetine after three (3) months due to weight gain and somnolence. MEDICAL HISTORY: She takes norgestimate/ethinyl estradiol (OrthoTri-Cyclen Lo) for the past 5 yearsfor birth control, vitamin D 2,000 IUOAM, and loratadine as needed for seasonal allergies.No history of surgeries. No history of head injury or loss of consciousness. HISTORY OF DRUG OR ALCOHOL ABUSE: She reports using marijuana socially," "once or twice per month" during her last year of college. No other drug use and no drug use since age 21. She has a glass of wine with dinner two nights per week. She has one to two cups of black tea per day. FAMILY HISTORY: Patient was born in a suburban town and raised by her parents. She has one sister, age 38. Her parents divorced amicably when she was age 18. Her father is remarried and her mother resides with her boy-friend.