Thank you Rhiannon. Are you also combined feeding
I no longer bf but combi fed my daughter for 2 years. I dropped my feed very gradually and didn't have a huge shift hormonally as a result. My daughter also got used to the feed going as it was a slow process. It's important to choose your timing as well, as my daughter wanted to feed more when teething or ill, so you want to make sure you avoid those times ideally when dropping a feed.
To ensure your supply changes gradually and alongside that your hormones, it's best to start with changing one feed to formula and once that's established, you can then drop another bf and change that to formula and so on.