5 mth old waking all night?

My son hasnt slept through the night since he was 3 months old. He wakes up to nurse about twice a night and just flops around then cries if I'm not holding him about 4 times a night. I can't put him down or he wakes up. This is getting out of control, why is this happening? I know they say to let them fuss a little at night but when its 4 am I just want sleep. I stay at home with him and my husband is deployed so he is very attached but what can I do, I have to get some sleep. HELP!!!!!!!