Olympic - that's not a great experience you've had.
I'd agree that "we" are changed by childbirth - I myself have an interesting overhang thing going on on my belly from babyweight eldest is nearly nine
But, it's bollocks to suggest that you should accept it. Total bollocks. And It Makes Me Cross. See fizzyo's great post.
Where you go from here is - go back to your GP. Report what your treatment has been and what problems you are still experiencing. State that this is not acceptable to you and that it is interfering with your life, and whether it is bothering your mood (depression is quite high in women with continence issues. Quelle surprise)
Ask your GP to refer you to a specialist physiotherapist or a uro-gynaecologist.
Assuming your injuries to your undercarriage haven't damaged any nerves then doing your exercises - even without having any sensation you will be having an effect. It's just really disheartening.
To help that - you can buy feedback gadgets. They are expensive - from about £100. They are fitted with a scale of some sort, so you can see the dial move as you work the muscles.
And, you can buy muscle stimulating ones, which give your pelvic floor a wee electrical helping hand.
This is ordinary muscle training stuff - if you'd been in plaster for weeks and had a scraggy arm that was weak you'd do exactly the same stuff to get it working. It's just a bit embarrassing when it's your special place that's a big saggy.
PM me if you'd like to moan let off steam. Happy to give advice, and I could try to find out who your local fanny guru is.
Please don't put up with it. You don't have to.