transmission problems

[newtron]

I have a 2002 Ford Focus with just over 60,000 miles on it. It runs very nicely, but the other day for about 4 hours, it was very difficult to shift gears (it is a standard), especially going into reverse. It felt as if the clutch was not dissengaging fully. The transmission fluid level was fine. After a few hours, it began working fine again. Is it possible that this was just a one time fluke caused by a random air bubble or something, or is it a clue that something is wrong with the transmission and will only get worse? I really don't know much about tranmissions. Thanks in advance.

[newtron]

Maybe I'm being thick, but the users manual said that the "clutch oil" was added to the same reservoir as the brake fluid, and apparently was distributed by the same master cylinder. It's been a few days now, and my wife drove it about 1000 miles to Las Vegas and has been driving a lot in the city, and everything seems to be working fine.