Sleep Training

My angel is still a bit sick but his eyes and ears are definitely clearing up so hopefully tomorrow he can go back to creche and visit his friends.  Last night Cole screamed for a full 2 and a half hours 12-2.30am my word, my arms are actually physically aching from picking him up so much, which I know is the first mistake as my domestic likes to tell me, "you spoil him too much" but the thing is I just dont have the energy at night to listen to him cry so I would rather pick him up and rock him, its a sad cycle because every night im tired from the night before so I just need to sit down or stand up and let him cry it out, why why why is it soooooooooo hard!!  Why wont the monkey sleep?????