honestly making the toadstools a limited resource is stupid. especially when your trying to grind for money to get better gear.
eventually you'll only have reed as a party member. and you only get tiny amounts of money for beating zombies. considering that the latest weapon for me is 1500 and the max i got from zombies is 80. also stuff you can interact with should have a highlight or something.
also why do the zombies keep targeting makoto? shee keeps getting infected running out of toadstools, as i said baffling design choice.
also about the gear. zombies pack to strong of a punch. maybe they wont if i buy better gear but as i said before. its way to expensive

I'll take some of this under consideration.

Reed's immune to the infection and His Protect Skill covers against all attacks at the entire party. There is no Specific targeting Logic that goes after Makoto, it's completely random.  The Idea is you need to make a choice between going on an all out offensive, and risk Infection to the decidely more fragile Makoto, or have Reed tank for Her while She attacks. Once you collect more of the party it'll ease up.

Also while you can Grind, i've placed items in various locations. that you can get for Free. Grinding is not efficient and dangerous to boot, but it's an option.
Hard to say were you are at this point in the game, but a few levels and the difficulty will ease up.