Mraw, as L says, I think you sound a little overwhelmed by it all, so start from the bottom.
Get everything for your wardrobe, throw all the ridiculous hand-me-downs away. Sort out a few pieces that you feel good with. It's a difficult transition to go from no DCs, some-one who cares about fashion, goes out a lot & whose wardrobe reflects that, to a working mother. You have to completely re-think what will work for you.
So you're building from the ground up, you need foundations, what do you do everyday? You're a HCP, I guess you wear uniform at work so not too much to think about there. So casual, always a good place to start (but not so easy - it took me years to learn how to dress casually, it's not as easy as it looks.)
If I was starting from scratch, I would look for a good pair of jeans, ignore fashion in this case - every-one is skinny crazed atm - try on lots of pairs, see what suits, with your height & size, try a straight leg that can be rolled up & worn with flats or heels.
Once you have the jeans sorted I would look for skirts, shirts, tops & woolens - you favour a 40's style - there's loads out there - go with it - it's you & it is practical - why not? My natural style veers between 50's & 70's (I love a 70's mum look, equally I adore a 50's Dior New Look) - just a cut in a certain item can bring it all together.
So get a shirt, a few tops, a decent bra, a couple of bits of knitwear, a skirt & a dress & you've got quite a few outfits going on there already.
Two pairs of shoes maybe, if you're into 40's, a flat, lace-up granny shoe & a glamorous block-heel & you're there.
A tweed coat from ebay or a vintage shop would look great.
& if it's 40's you're after only do a scarf if it's on your head.
Get ya victory rolls in (do wonders for thin hair), whack on a bit of tinted moisturiser, a slick of liner & mascara & red, red lips.
Job done.
Have fun with it, don't stress, it's only fashion, too many people take it too seriously, don't worry what anyone else thinks. Do it for yourself.