Why would my five month old baby scream uncontrollably waking up from his sleep?

Any ideas? It's not a regular cry but one that's horrid... screaming like he's going to die. All I know that I did differently was feed him a little bit of carrot puree. I put him to sleep in our room and I wasn't there yet in bed... could that be it. Let me know what you guys think... I'm concerned.