I had low vit D when I got my bt results at the start of this pg. I took the ostelin but not religiously . My GP never mentioned bub needing anything (IMO that seems OTT!!) I didn't go for the follow up bt which she wanted me to do at 12-14 weeks either
I try to get out in the sun a bit more. Usually if I am hanging the washing out in the morning I will sit out there a little longer and soak up some rays!
With my previous pg there was never any mention of tests for vit D (I believe it is a newer test that they are doing to all pg women now).
My most recent bts showed no probs.
Just take the ostelin for now. I'm sure everything will be fine