Yes, you do need to trust your range.

I almost didn't respond at first since this has never been much of an issue for me -- I have a weird spacial sense where I can pretty much see distances and such better than than some people can do by measuring.

We were practicing knife vs. knife (combatives not boxing of course) tonight and a big part of the drill I setup for my friend was getting within range of hitting his hand and also sometimes leaving my hand out there a little for him to "see" it was in range.

As you might guess, range and judging distance with knives is even more critical since almost any knife 'touch' does some damage and a good strike can lop off a finger or worse.

Keep practicing. A big point in your favor is you are trying to WORK the drills and truly PRACTICE rather than just doing exercise.

Keep up the work -- pay attention to the details like you are doing and progress will be fast and sure for you.