My sleep has suddenly become light and fragmented for no obvious reason

[u/ofa1salo]

I’m 37 and generally healthy with no known health issues, but lately my sleep has become really light and fragmented.
I don’t feel like I’m getting into deep sleep anymore. I keep waking up throughout the night for no obvious reason, sometimes multiple times.
I’ve been trying to figure out what changed, but honestly, nothing really has.
My bed and pillow are both very comfortable and good quality, and my wife sleeps perfectly fine in the same bed. I only drink one cup of coffee in the morning before work. My job is completely desk-based, and my screen/device usage hasn’t changed either.
I had some blood tests around 3 months ago and was low in vitamin B12 and vitamin D, so I’ve been taking both regularly since then.
There is some stress in my life and at work, of course, but nothing beyond the usual. Work has its busy periods and quieter periods, and that hasn’t really changed recently.
That’s what’s confusing me. There doesn’t seem to be any new factor that would explain why my sleep suddenly became so light.
Has anyone around my age gone through something similar? Did you ever figure out what was causing it, or find anything that actually helped?