Suggest Treatment For Sjögren Syndrome And Interstitial Nephritis

Good Day I am 33 years old and was diagnosed with Sjogren syndrome after my daughter was born. The diagnosis was made by doing a kidney biopsy and this was in 2008. Since I have been on lots of cortisone and immunosuppressant drugs. I have also been diagnosed with interstitial nephritis. This past year I have been struggeling with repeated e-coli infections in my kidneys. (3 in the last month alone). I had an abodminal sonar done on Friday, with specific attention given to the kidneys. They found cortical thinning of the kidneys, but also found suggestions of nephrocalinosis. I am stressing out about this because I am struggeling to get hold of my doctors. Is this serious, should I worry and if it is the case, how is it treated? I currently weigh 97 kg and I am 1,62 m. I am using Medrol 4 mg daily and Methotrexate 20 mg per week. I would really appreciate some advise. Regards Jaan-Mari