有点别扭.better if:
I suddenly felt afraid that I had never felt before
可以简单点:
I suddenly felt afraid that I never had before
felt afraid that...没问题.
这句话的关键问题在:"had never had before" ...后面的had应该为felt
我猜你想表达had never had "this feeling" before,如果你把this feeling加上去表达会更顺畅