Hello and welcome, to the forums and the game!
This is a subject that has come up a lot down the years (a search for “herb phys-reps” could prove useful).
(here’s one for starters: What do you use as healing physreps? - #2 by AnthonyHJ)
In terms of what you NEED, very little. Props and phys-reps are generally appreciated, so here are some ideas:
Small bottles are available online from a lot of places, or at the events.
(ebay potion bottles - Google Suche) …okay, there are thousands of the things… I blame Harry Potter.
Alternitively you can likely pick up a few if you keep an eye out for them: Miniture spirits bottles work pretty well, as do some small condiments bottles. Second hand shops may also have several as props/knick knacks…
Filling them: Unless you do something like glue the lid on, or make a wax seal, it’s safe to assume that at some point some player will get carried away and try to drink the phys-rep. Make sure it’s not toxic.
Things I have used:
Lemonade with food colouring and edible glitter
Water with food colouring
Brandy with chopped ginger
And as a rub-on salve, cucumber scented moisturiser cream.
Bearing in mind you probably wouldn’t be carrying around fresh plants, so dried herbs, oils, tinctures and concentrated teas would be fine, and look good.
For the potions, any little bottles, maybe with useful labels on them?
As a hint, what you will sell a lot of is Elixir Vitae (basic healing potion) and Bloodharrow Philtre (Anti-venom).
A wooden box of some sort to carry potions in on display, or even just a satchel stuffed with racks of bottles and similar, works well.
But you can get away with a couple of small bottles of stuff stuffed in your pockets, and somewhere to keep the herb/potion cards.
As for playing an apothecary…
I would reccomend taking a herb garden as a personal resource. You will spend a lot of time buying and selling herbs for your potions, so be ready to do a fair bit of walking. I would strongly reccomend a small notebook to record your recipies, their ingredients and effects. So you remember what you need for what.
Potions are one of the few things that can be made in play, but unless you want to pack a full distillation kit, and be found playing with pestle/mortar, adding little drops of X to Y, and singing charms above your cauldron… (which can be fun, don’t get me wrong), and even if you do… you’ll be spending a while waiting at the GOD queue.
At GOD (Games Operation Desk), you can hand in your herbs, show you have the recipe for potion X, and get a card for potion X.
And then you return to the field with a stack of potion cards to sell.
There is an apothecary guild I’ve seen in play, they make potions for commission. You’ll have to investigate them in play 
I would suggest you become known to your group/nation as an apothecary, and they will likely sell you herbs cheaply in exchange for stocking them up with potions.
You may also want to ask around and investigate the extra recipes available, including some new and nasty Druj ones…
(don’t ask about the poisons…)
…to diversify a bit into new and different recipies. Every apothecary on the field can make Elixir Vitae, but only a few will be making something like the Tonic of Surging Flame…*
If you want to keep your focus as apothecary, that should cover it. If you’d like to combine that with general healing or buffing your friends or fighting on the battlefield yourself, ask away on that 
*This potion makes you very difficult to kill, but gives you the reckless courage and life expectancy of a Dawnish Noble on a sugar rush. When I played an apothecary, I made it once, and eventually sold it to a Dawnish noble on a sugar rush. Roleplay effects of potions can be… interesting.