wrong
166/day plus your current salaries (which includes part time jobs)

MY ANSWER

SHELTER
Make a camp 5-10 meters away from the sand line.
First build a roof with the tarp and funnel empty bottles found on the beach to catch rain water from it.
Then make an elevated wooden floor from materials like tree trunks or bamboo.
This is to prevent insects and unwanted critters to climb on you while you sleep.
Just lay down palm leaves to make it as comfy as possible.
Maybe you get lucky in finding Pandan/Mengkuang to make mats from it
You can burn coconut husk or drift wood below them at night to repel mosquitoes and sand flies.

FOOD
Get a few coconut, good source of electrolytes and also you can use them as bowls.
Save coconut husk to start fire from ember
Then using palm leaves, rattan or bamboo, you can make a trap for fish and crabs.
Forage the shell fish around the swamp/beach for bait.
Put the trap early morning, and collect them at noon.
That will be majority of your protein intake,
since fishing with rods and hooks OR casting nets is out of the question.

Smoke the excess fish and dry them on the beach under direct sunlight.
Dried fish is how people survives back in the days without refrigeration.

Go to the swamps and look for dead trunks, maybe you found some worms that is worth eating.
Some swamp trees can bear fruits like Apong/Nipah, but those are delicacies.
You can also cut the tree and get the sap for natural brown sugar. Known as Gula Apong.
Similar process like getting Nira butt is easier cause you don't have to climb a coconut tree.

If there's bamboo, then you can eat the young shoots.
If there's wild banana then you can eat the heart flower and inner core
If there's young coconut, you can eat the inner core called Umbut
If there is fern, there 100% will be Midin, fresh to eat.

You will be out of carbs anyway, just consume a lot of fish, they might be fat in them.

Most of your meal will be parts of fresh fish, dried fish and edible plants broth.
Keep them heated in the metal pot to prevent spoilage.

WATER
Trap them using the tarp as mention above. Just stock them in bottles during rain.
Dig a well 5-10 meters away from the sand line, maybe 5-10 feet deep.
Construct a ladder and a hoe in the process using available wood around you.
Get a bottle and rope found on the beaches to collect water from the well
Boil them using metal pots.

HYGIENE
Just put mud on your skin when going through the swamps to repel insects
Lit up fire using old coconut husk and let the smoke runs through your shelter to repel mosquitoes and sand flies
Make an outhouse far away from your shelter to prevent flies and water contamination
If you can find wild ginger/tumeric, make it into a paste and put it on your face as sunscreen
Or just weave a hat from whatever available.
Just shower in the sea naked, and wear dry clothes all the time

ENTERTAINMENT
Just masturbate 3-4 times daily.