Mine are turning out quite awesome. I see them as great "let's go stay with your mum for the weekend" bags too (facilities are, how shall we say, not always great).
WATER
The sawyer mini sp128 - I've always wanted to try filtered water and this is my glorious chance!
Purification tablets
FOOD
Camping cutlery kit
Seven oceans emergency ration food (basically shortbread)
Chocolate, Sweets mints
Tea
HEALTH
First aid kit
Dust mask
Diarolyte
Travel urinal
Caffeine pills
Painkillers
Sunblock
SLEEPING
sleeping bag
Eye mask
Earplugs
Pjs
Inflatable pillow
EvaQ8 foil blanket
STAYING WARM AND DRY
Instant heat pads
Clothes (spare outfit including thermals, hat to keep head warm is crucial, lots of socks, and light shoes)
Micro towels
Umbrella
Poncho
LIGHT
Portable wind up torch
Coghlans survival candle
Regular candles
Wind proof matches
HYGIENE
Mini toiletries
Face wipes
Toilet roll
PRACTICALS
Gorilla tape and superglue
Batteries
Wind up charger
Scissors
Detail wipes
Bin bags
Tin opener
Certificates (except I don't know where these are anyway, so fat chance)
SURVIVAL (hah!)
Folding knife
Distress whistle
This sounds like a hell of a lot but I mostly just grabbed our spare things and pushed them into bags. Always been a bit of a camping enthusiast/Girl Scout wannabe anyway 
DH regards all this with very dry amusement. But he'll see. you'll all see!
seriously - it's good to be prepared and I hope it makes you feel less anxious, but if it's getting too much for you, might be worth talking to someone. 
Also, make sure you can carry it. If you can't, lose anything that feels "extra". It should basically be like an overnight bag but imagining you're staying somewhere with no facilities whatsoever I'm looking at you mum
I am also now beginning to realise that to be properly PREPARED I'd need to spend loads and have a spare bag in the car, house and office. That won't happen, so I'll stick to this and hope 
Good luck! Looking forward to seeing other replies.