What happens on the Astral Plane, stays on the Astral Plane
Towards the middle of the spell it states:
Your astral form is a separate incarnation. Any damage or other effects that apply to it have no effect on your physical body, nor do they persist when you return to it.
Your projection is not you. It is, literally, a projection.
Picture it like being in a virtual reality simulator. If you got stabbed in the simulator, you are not stabbed in your corporeal form. Should you actually find the thing(s) you are looking for, you can put it in your Astral pocket. But when the spell ends, you don't get to keep what's in your Astral pocket. Just like you don't bring back damage you took to your projection.
But...what about my stuff?
Part way through the spell it states:
Your astral form can freely travel through the Astral Plane and can pass through portals there leading to any other plane. If you enter a new plane or return to the plane you were on when casting this spell, your body and possessions are transported along the silver cord, allowing you to re-enter your body as you enter the new plane.
So that means that the stuff you grab becomes part of your possessions and appear on the other side, right?
Not so fast.
Earlier in the spell it mentions, "Your astral body resembles your mortal form in almost every way, replicating your game statistics and possessions." So the possessions you bring to the plane are the ones you started with. Then, when you walk through a portal (whether to a new plane or back to where you started), your body, and the possession on your PHYSICAL body, are teleported "along the silver cord" to the destination. If that later phrase didn't say possessions there would be the possibility of you and your possessions being projected, but when you go through a portal, only your body appears. Welcome to the Plane of Fire, naked.
So to actually bring something back, you'll need a different spell.
Using Gate or Plane Shift will bring your bodies to the Astral Plane
So instead of projecting, you need to actually go to the plane and get back your items. And I'm quite impressed that you found it/them; the Astral Plane is big. Really big. You just won't believe how vastly hugely mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to a whole Plane.