Change of sleep pattern

So my son is 5 months old and for the last two nights in a row he's been waking up constantly and is completely unconsolable. He's been a great sleeper since he was born. Last night he was upset from 1-4 am and Everytime we put him down he was upset. He just wanted to be held, he wouldn't eat, didn't need to be change and he didn't have a fever. He does have a minor cold, coughing but that's it. Does anyone have some advice? This tired mama needs it. A picture of my usually happy baby