Can you offer some advice?

I grind my teeth at night and my canines are now ground past the enamel.
This was confirmed today during my checkup and teeth cleaning.

My dentist is suggesting getting fitted with a mouth guard.

I tried that years ago but it was uncomfortable to wear....it was custom fit
but came out like the mouth guard you wear for physical contact sports. I
could not sleep with it....too bulky and suffocating for me. This old
mouthguard no longer fits as I have had 2 or 3 teeth capped since it was
made so modifications to it may not be possible.

Although insurance will pay for a new guard I have heard commercials about a
drugstore brand you can buy (not the sports type) that is supposedly just as
effective.

Any opinions?

Thanks in advance for your expert advice.