I have a 1998 Mazda B2500 with a 4cyl/5spd. It has high miles but ran good up until today. One or two times I heard a noise with the clutch in as I shifted into 3rd gear. Then when I let the clutch out it was fine. The clutch seemed to have plenty of pedal to get the car going and in gear. Now it makes a horrible noise with the clutch pedal pushed in. It still drives and shifts into all gears. Is this the throw out bearing? If so is that a shop only job to remove and replace?

Any help or ideas is appriciated, Thanks!