2.5 Months Left - What is a Must Have?

I'm adopting a baby boy that's due in March. For some reason it didn't really click until tonight that he will be here in less than 3 months!

That said I'm freaking out. I have no idea what I should get him ASAP. If you haven't adopted before; its hard because you don't want to over shop and have tons of baby stuff you'll have to either get rid of or put away in case you get re-matched.

Well... I have no idea what would be considered a necessity? What are some must haves? What should wait until the paperwork is handled (after he is born)?

edit to add: I have induced lactation and plan to breastfeed too.