When I was diagnosed in 2007 with CD , I had two massive rectal fistulas and my GI insisted that the only way to heal these is with remicade. Like you, I was scared to turn off my immune system for the fear of getting something worse then CD. I did a lot of reaserch and decided to go with the SCD diet approach and using a more mild drug like pentassa. My GI said diets are just a scam and they will never work in healing CD or fistulas and I am wasting my time.
Well, after 7 months of fanatical dedication to the SCD diet, both fistulas were completely healed up , and all my other symptoms like blood and mucus in my BMs were gone completely gone. That was in 2007, and too this day I have been 100% symptom and fistula free, and I still follow the SCD diet ( but not as fanatical as before), and I take pentassa.
I suggest reading the book "breaking the vicious cycle" which goes into detail about the SCD diet. This diet seems to work best in people who are newlly diagnosed without a lot prior damage in your intestines. You have nothing to loose by trying it, and all to gain if it works for you.