Significado de ''It's got a hold''

Hi, guys!
There's a song by Tom Walker called "Leave a light on".
In the first part of the song, it says:

"The second someone mentioned you were all alone
I could feel the trouble coursing through your veins
Now I know, it’s got a hold"

However, I just can't understand to what the "it’s got a hold" refers to, or how it could be replaced.
I love the song and I would be relieved to finally get this clear.
Thanks in advance.