I wonder is it normal to have my abilities deteriorate so fast?
There is no "normal" course for MS; one person can have one set of symptoms, another person quite a different set; one person can deteriorate quickly, another person may get back 100% after a flareup. This is an unpredictable disease.
Many people choose to use the approved medications; some of us have tried them, without success, and now opt for a treatment of diet and exercise (especially after reading Dr. Wahls' dramatic story, http://www.TerryWahls.org
I encourage you to assemble a medical team of physicians (GP, neurologist, maybe even an endocrinologist) you feel comfortable working with. My best to you.