Most people on here know how you feel.
I had my little cat for ten years which I feel extremely lucky for to have known the beautiful little beast. She only gave me gyp twice, once she got locked in a shed (snuck in) and I realised something was wrong and went out and almost scented the air for her. If I'd had whiskers they would have been quivering, I knew something was wrong. Then I heard her screaming in the shed:)
Second time she'd just snuck into a neighbour's house through the window and I flouted all property laws and clamboured in through the windows to dig her out.
I think she died through Bob Martins which is a whole other story and makes me furious, but I was trying to say people understand how you feel, it's horrible when you don't know where they are.
Actually ever since my one was pts I've had people say 'I know this is a funny thing to say about a cat...but she was very intelligent, wasn't she?'
Yes she was and I was so pleased to have known and loved her.
Best paws thoughts for yours