Meouw, Meouw MEOUW, MEOUW!!

My kitty cat Squeaky (real name: Galileo) is the apple of my eye.
He is 9 years old and I have had him since he was 7 weeks old.

I got him and his related brother Boomie (real name: Da Vinci)) together, but Squeaky was always the mommy's boy, while Boomie liked to explore.
4 years ago Boomie disappeared. He was never found.

Squeaky became my sole companion, save for a persian houseguest who lived with us for a few months.

I have moved house so many times with Squeaky that I have lost count.

I am now in my own place and I am so happy here. But Squeaky doesn't seem to be. All he does is cry...and cry... and cry.

Sometimes I will find him lying on the floor just meowing in general. It is beginning to drive me insane! I walk with him every night through the complex and I leave the door open for him (Brrrrr) until I go to bed.

As I type this, I can hear him meouwing as he walks around the complex.

The only time he stops is when I am stroking him or we are at the scratch pole together.

Could he be lonely? I am only allowed 1 pet, so a companion is out of the question. I work long hours. Maybe he is just really lonely?

I have consulted various animal behavioural sites and they say to ignore him when he cries. But what if he is crying because he is telling me that he is lonely?

He has never cried like this before. Even when living with the Persian cat, he was unhappy, but never this vocal.

It has been 3 months now.

What is going on??