1998 Honda Prelude clutch problems?

last night i bought a 5 speed 1998 honda prelude, base model vtec. it was working great when we test drove it, drove over an hour back home, and drove for a few hours that night. i was at a stop light and i put it into 1st gear, then second, and i noticed the speed stayed the same and RPM's went sky high. No noises or anything with clutch, no grinding, etc..but same thing happened in 3rd and 4th. i could only drive 25 mph tops. i let it sit at a friends over night and came to get it the next morning and it worked fine? what could the problem be?