You need to place things in your pouch seperately as there is limited space for what you can carry, you can also set up item sets to auto-replace your pouch contents from the stock in your item box. Go to your item box, take out everything you want in your pouch, then use the menu options to mark it as a set.
Or perhaps youve used them but not restocked your pouch from your item box? What I do is use a page of my item box as a 'ready room' that is arranged to have all my regular items in the same order across the top as I usually have them in my pouch- potions, steaks, whetstones, farcaster, paintballs, traps, tranqs, etc. Further down is more specific stuff like flash bombs, hot/cold drinks, antidotes, lifepowder, mega dash juice, etc. Before each hunt I just go to that page and restock my pouch from there.