Suck it up. I've been doing groceries with nothing but a bike and the public transportation system ever since I moved out of my parents' house.
Can I hire you to do my grocery shopping? My last trip entailed a 35lb container of scoopable kitty litter, a 12-roll of paper towels, two gallons of milk, and around 13-14 plastic bags of groceries. You're clearly superior in long haul carrying skills than I am, so I would love to contract for your services as I confess I would struggle with all of that on a bus OR bike.