You can do this.

I have ADHD as well. This is what I'd do to manage being short on meds:

• Give work/family/loved ones a heads up that you're going to be off your game for the next few days.

You can keep it short and simple - if you don't want people to know the details, tell them that you're going through a change in meds (because you are, just not in the way that people will assume.) Use this as a legitimate excuse as needed.

• Reduce your demands.

Try to avoid any big responsibilities until you're back on your meds. Postpone and delegate what you can. Take leave from work/study if you are getting overwhelmed or you're not capable of performing. If you can't take leave then see if you can work half days or to start later in the morning.

Expect that you're going to experience some withdrawal symptoms - sleep disturbances, headaches, irritability, low mood, lack of motivation. Give yourself the space to manage this stuff. Remember that it will pass in a couple of days.

• Use caffeine.

Better to have a mild stimulant effect than to go without any stimulant effect.

• Consider supplements.

If you can get your hands on L-dopa, tyrosine, and/or bacopa monnieri (brahmi) easily then you might find these useful. Some people swear by these supplements for ADHD.

• Consider speaking with your prescribing doctor about adjusting your medication.

A lot of people who take extended release stimulant meds have a prescription for a top-up short acting dose for late in the day or if their meds aren't working as effectively (for example, menstrual cycles wreak havoc with dopamine and ADHD meds so it's often necessary to bump the dose up due to your cycle.)

If you get a script for a top-up dose you can keep it on hand as a backup for the next time that you're short on Vyvanse.

• Consider stockpiling some meds in the future.

On a related note, lots of people with ADHD take tolerance breaks or medication vacations. Sometimes you can get away with skipping a day's meds - if you have no commitments, if it's a weekend, or maybe if you decide to sleep in. That sort of thing. Stash those spare meds away somewhere safe and use them as a backup in situations where there are supply chain issues or you can't get in to see your doctor for a new prescription or similar.

Good luck!