As difficult as it may be try not to get frustrated, you’ll only end up rushing and dying more. If it gets to that point don’t be afraid to just put it down for a while. Souls games aren’t hard, you just have to learn how to play them.
Don’t worry about being hollow for now, you’ll die so much on your first playthrough you’ll run out of humanities pretty quickly. As others have said you can use them to kindle bonfires for more estus, it’ll cost you 2 humanity (1 to reverse hollowing and 1 to kindle). The number in the top left corner of the screen is how many humanities you have available to ‘spend’, you can consume humanity items from your inventory to increase that number, and you can farm them from rats - there’s a good spot under the bridge with the dragon.
There’s also a vendor hidden in the Undead Burg that sells the Heater shield which will probably be pretty handy early on.