The only way to get your men back is to beat the lord that fought you in the first place and recruit his prisoners into your army(hopefully your former army is still there).
Considering you only have 3 units left, this is probably out of the picture at this point.
In game, you can consult with all your lords before appointing a fief, then appoint the fief to the lord who has the most supporters amongst other lords. This should limit the negative relations hit to the lords who did not support the lord who eventually gets the fief.
Failing that you can modify your game using the module system to lessen the relationships hit. IF you're not familiar with modding the game and the module system this can be a bit of a challenge, but the way to do it is:
Find the file module_scripts.py, and look for the script give_center_to_lord.
Find the line:
(val_clamp, ":relation_with_liege_change", -5, 3)
This line signifies that the relationship change between lords and liege when awarding fiefs varies between -5 and 3. Change those values to whatever you like, for example -1, 20.
Note that this change will also affect other kings, so this makes getting their vassals harder.
To make the change only affect the player, change the line by this piece of code:
(try_begin),
(eq, ":faction_leader", "trp_player"),
(val_clamp, ":relation_with_liege_change", -5, 3), ##CHANGE THIS LINE HOWEVER YOU'D LIKE
(else_try),
(val_clamp, ":relation_with_liege_change", -5, 3), #THIS WILL BE FOR ALL OTHER KINGDOMS
(try_end)
Again, change the values in the above piece of code to whatever you want.
Source: talewords forum.
Best Answer
You may only take prisoner people you have knocked unconcious. You must first take down the Lord, then take down their armies. However, if you take a Lord prisoner he may escape after some time traveling.
Escaping: For every 72 hours the Lord is in your party he has a 50% chance of escaping. If you have a jail in your town, you can put him in their and he only has a 10% chance of escaping
Source:
http://mountandblade.wikia.com/wiki/Prisoners