How old are you?
Is this a post-baby dress-identity-crisis? It's very common.
I can't give you anything specific - I don't know you but I'm happy to tell you what I did. Not that I'm particularly stylish or beautiful! But I did go through that thing of wondering how on earth I should dress post-baby.
The first answer is kind of obvious - there is nothing, at all, to stop you dressing the way you did before. But it's not so simple, is it? Maybe it was just me, but it didn't feel so simple, somehow.
I found that during pregnancy and the first few months I'd slightly fallen out of the fashion-loop. And I felt I'd "changed" (though I couldn't put my finger on how) and I didn't know how to get my identity matched with clothes, partly because I didn't quite "know" who i was.
All this is probably self-indulgent twaddle!
What I found helped:
I went on an intensive course of window-shopping. I put baby in a sling (and put him on the floor in the changing-room - though sometimes he would be cuddled by shop assistants - I still feel particular love for "Office" shoes on King's Road!) and went out and just looked and looked at clothes, and tried things I liked on.
I also stared very hard at women who's style appealed to me - and tried to work out what I liked. And I looked through magazines (on the cheap, in Sainsbury's!) to look for things I liked.
A bit of confidence came back. I started to buy things, and experiment a bit - and I really used the returns policy shops have these days.
I spent a lot of time in jeans and a T-shirt. But that's OK - most people do!
I'm not fashionable by a long chalk, and I suspect I often look a bit eccentric. I'll never make "groomed" but I do think I've arrived back in the place where I think clothes are fun, rather than a bit mysterious.
Hope some of that is helpful! I know none of it is going to help with the immediate problem of the Take That concert - but for that you'll need to put a bit of a word out about what your usual style is, and where you want to pitch yourself fahion-wise.
Eg. If you're a 40-something woman, it's (still) all about colour-blocks. Though you could try tight cargo-pants and an "ironic-serious" rock top. but that's 40-somethings!