Cats screaming really worryed?

I've been in bed and there a cat non stop screaming outside my window for the parts 20mins the screams started short and then ended with BIG SCREAMS and crys and meows so I went outside wif the torch just incase they were my cats and I couldn't c them anywere but in my bed they sounded so close anyway the screaming stopped so I came bak inside I went bak to bed and 5 mins later there were 2 mive and I meen really loud screams then it all stopped can someone tell me what they or it was yelling about