Corona advice/help

Hi. I have been diagnosed with Inflammatory arthritis and receive an Intramuscular steroid injection every 3 to 4 months to treat this. Unfortunately the Rheumatologist is unable to prescribe any other treatments as yet as I have ongoing liver inflammation. Despite various investigations the Gastroenterology team are unable to identify the cause of the liver inflammation. I also have Fibro, Osteoarthritis, sleep apnoea, underactive thyroid had a BMI of 38.9. I last had a steroid injection on the 9th of March. The Rheumatology nurse advised me to shield when I asked for guidance two weeks ago . However she appeared confused with the advice she was giving. I thought I may receive a letter from the NHS advising that I shield, however I have not received a letter. I have contacted my GP surgery who were unable to advise. Has anyone any advice to assist with this please? Thank you