The clinic itself may be able to provide some food, but I'd recommend you hunt or scavenge for yourself. For everything you mentioned.
There are stores and abandoned buildings scattered throughout the city that contain any number of items. Sift through the garbage until you find something workable.
Miss Unohana's clinic at [x,y] is always open to house those in need. There are also shops around that occasionally are restocked with food and other supplies, or you can scavenge the abandoned buildings in the Safezone.
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