You don't need to replace the rotor.
Can you post a picture? I'm a little confused with your post.
Basically you remove the caliper, pull the rotor off, and then you have the bearing hub still attached to the spindle. Remove the nut from axle and pull the bearing/hub right off.
I think from your post that you took the hub/bearing/rotor off all together. In that case try some heat around the hub/rotor seam.
It may be easier to put it back on the truck, it can be a pain to get them apart (read as 'bigger hammer').