how to not get overstimulated at the grocery?

the title is pretty self explanatory but yea. i dont get overstimulated everytime i go shopping but right now im on the tail end of my period so im pretty sensitive. im planning to go out to help my gf with groceries tmrw and im worried ill get overstimulated and wont be able to help much 😟

thanks in advance to anyone who can give tips!