Everything I've read on this forum and elsewhere has indicated that Ostarine is only slightly suppressive. Your testosterone might be extremely low for you to be completely shutdown when taking Ostarine.
Even though Ostarine is only slightly suppressive, I have seen numerous recommendations that DAA be stacked with it. So, what you're experiencing could be partially true and a placebo affect. It's still odd what you're reporting when you say "suppresses me instantly".
I'm currently taking Ostarine at 12.5mg. I'm also stacking it with DAA and Universal Animal-Test. I'm doing well in the libido department with this stack. You could look into it.