for me, @A MyMSTeam Member nailed it - it takes time, baby yourself; your immune system will be compromised so take precautions to avoid infections - mostly, rest, rest, rest (you probably won't to do anything else anyway!)

I haven't had results that quick before either but everyone's different :)

should have worked at day 2 or 3

I recently finished a 5 day 1gram dose of solu medrol after all the side effects from the steroids started to ward off I finally could finally concentrate on getting myself feeling better, the side effects from the steroids lasted approximately a week and then not long after that I slowly started to regain some feeling back in my legs and 2 weeks later was back at my physio and happy to report I regained full sensation back and walking normally again well as "normal" as I walk. Take care and keep pushing forward after you get some rest!!