1994 Accord Transmission problems?

My 1994 Accord (128,000 miles) is a stick shift. A few months ago it started popping out of fifth gear when I applied the gas unless I physically held the stick in place. Two days ago it started doing the same in third. I was told not to worry, that it indicated a couple of worn knuckles. Now, it is very difficult to get the car into gear. I have to repeatedly double clutch to do so. The car makes a faint, rapid clicking noise whenever I engage the clutch. I'm not experiencing any fluid leaks and the only other noise is brake squealing. Thanks