leaking clutch fluid....help!

i drive a 98 2.2 5 spd. s10 and i have major problems with my clutch, but ONLY WHEN IT'S COLD! it will leak almost every drop of fluid out of the resorvoir, but i dunno where it's leaking because i don't see it on the driveway. it causes me to have absolutely NO CLUTCH in the mornings when i get up for work on a cold morning, so i just have to fill it up and drive for the day, which will usually do ok until the next morning! does anyone know what may be causing this or had this same problem before? like i said it only does it when it gets cold, but winter is here and it's getting VERY annoying...all help is appreciated! i've got to get this fixed!

replace the master cyl.
it happens. its the seal going bad. should be a pretty quick job, and you will need two people. Should be too expensive either.