Bra wise with DS1 I was 16wks and went from a small c to a DD after his birth I was an e then settled to a dd. DS2 which was 9yrs later I was 12wks went from c to d to DD to e back to DD again. I bought some dale bra's from bras n things and took the underwires out then switched to the maternity towards the end
Centrelink i had a crn as my ex DH left when I was 16wks. I didn't bother organising my ppl until the wk after DS2 was born as I was on 15wks paid leave from work first. Ppl has just kicked in. When you've got your my gov account you can link everything to get letters etc all online and no paper ones. Install the Centrelink and Medicare app on your phone use the same password. When your in hospital with bubs they will give you the paperwork for Centrelink with a unique code with will match up to their end for their proof that you've had the baby. You don't need to go into the offices at all to do any of this. I sat on my computer and did the lot same for the birth certificate.
Now for tmi, if you get majorly "blocked" up microlax 5ml will be your best friend, trust me, instant relief omg. I had c-sec and the drugs block you up big time.
Drink lots of fluids all day everyday even in the middle of the night. Rest when you can and take a nap when you can. Get a cleaner towards the end if you can afford it. Make lotsa meals to freeze when you finish up work.
Don't go bonkers buying our baby bunting it's hard not to. There is so much crap in those stores you don't need half it.
Take pics of your belly every couple of weeks. I was monthly as I didn't get bigger until my 7month
Enjoy your bump from what I've read on here it's taken you a while just like it did for us.