After being on Suboxone for a period of time, it is not unusual to lose track of your dosing. For one thing, you forget because you're feeling better. It may be a sign that you're ready to taper your dosages.
Suboxone acts over a long period of time as well. So even if you miss a dose, there is still probably some left in your system.
It is NOT recommended that you double up on the next dose and don't "freak-out" about it. If a patient misses a dose of the medication, they should simply just take their next dose at their normal time.
Obviously, let your doctor know as well. If it looks like a good time to start tapering, you can both make that decision.