93 ford ranger clutch problems????

I have a 93 ford ranger that just recently started acting funny. The main problem is when the truck is turned off you can switch gears fine but as soon as you start the truck you have to push as hard as you can to get the truck into gear. any help would be appreciated.

How many miles on the truck/clutch? Could be a slave cylinder issue, throwout bearing issue, or just a plain'ol worn clutch.
G/luck
Joel