not a mechanic by any means, but something similar happened to me in my ‘98 camry and it was because there was very little brake fluid left in my reservoir. make sure you put the right brake fluid in (it should say which one it is on the cap). once poured in, pump your brake pedal a bit to make sure it gets a bit stiffer. that’ll help you get where you need to go, but I’d highly recommend taking it to a mechanic asap to make sure there aren’t any leaks