Was diagnosed with MS in 2005, I used Rebif for first 5-6 years, GI system finally fell apart and symptoms were tough. Then using Aubagio and really liked, but now almost 12 years, head pain and right leg pain and starting to loose function and use of right leg. The past 6 months have really been tough physically and mentally. Doctor is suggesting Ocrevus. What does this involve and what are expected systems?