I have a 2003 Ford Focus SVT with a 6 speed.

I have a 2003 Ford Focus SVT with a 6 speed manual transmission. Recently, I have noticed that it is hard to get it into gear while driving. The clutch pedal seems a bit loose, but not too much more than usual. Occasionally it has trouble shifting and then sometimes it is completely fine. Once I am on my way there are no other problems when it is up to higher speeds. When the car is off, I am able to shift it into each of the gears easily. This afternoon, I was in the process of driving and trying to shift when it just refused to go into any gear. I finally got it into third gear and into a parking lot. I turned the car off for a few moments and turned it back on and was able to get it into first and second again. I am wondering if this is a problem with my clutch, transmission or both? I am concerned about the hight cost of what it would be if it were indeed a transmission problem. Any advice you could give would be greatly appreciated. Thank you.