Mid 2000s film about a drowning?

Basically when I was around 7/8 I watched a film with my mum which I have vivid memories of. In the film, a woman was on a ferry with her son and after she falls asleep in her chair, he disappears. There is a strong insinuation that he drowned but I can’t remember if he actually did. Next thing I remember is that she has to identify a body found in the water and I think he has a badge or something on his clothes that makes her sure it is him. The only other thing I remember is that I think later on she saw a random kid and genuinely thought it was her son and it freaked out his mum. I watched this on TV in the late 2000s I think, so it must have been released a few years prior. Any help would be appreciated this has bugged me for years!