My fussy 6 month old baby cries too much. Should I let him cry-it-out? How to go about it? HELP!!?

My baby boy is the epitome of a 'high-needs', 'persistent-personality' baby. Everybody thinks so, including his grandparents. He is too fussy. He can't sit by himself for even 2 minutes, he constantly wants to be cariied & held. Even then, he's fussy. Whenever he wants to sleep, be it nap-time or bedtime he has to cry for at least an hour (while we are carrying him & swinging him around). It used to be OK but now he's getting heavy & he DOES NOT SLEEP unless he's carried in the rocking position & you have to stand up & jump around. At night, he sleeps at 10PM (after extreme fussing & crying). Then he wakes up screaming every half hour bcoz his pacifier fell out. I have to go back to work soon & I know nobody will be able to handle hm bcoz I'm his mother & it's hard for me too. Any suggestions? I'm thinking about letting him cry it out but I don't know how to do it. Will it work on my fussy baby? I doubt it bcoz he's ready to go screaming & screeching for hours at end unless he gets what he wants. Please help me, I'm desperate!!