Best Answer - Chosen by the Asker
Native speakers, including me, will sometimes use "whether" in place of "if" in that case, but technically, you can't.
"Whether" can be used when you have possible alternatives. Otherwise, you use "if".
In your sentence, it seems like there are two options: you get help or you don't. But it's really a conditional, so you use "if".
I don't know whether it will rain on Friday or not.
There are two possibilities there, so you use "if" or "whether".
I hope I got that right! Good question.
