Oh dear, this thread went a bit south quickly didn't it?
Firstly, Happy Birthday, OP 
I don't think being in bed on your birthday at 7am during half term is a sign of neglectful or chaotic parenting. It's quite normal, imo. And I doubt the child was starving. She ate the cake because she's 5 and it's cake.
I don't think, at 5, she is old enough to deliberately target your things OP. Cake is delicious, plasters are fun, helping mum with her craft project is fun.
If she's getting up before you and getting into mischief (which most five year olds would do) you need to arrange something for her to entertain herself with in her room. Have you tried leaving some books or drawing things in her room and a clock with the instruction to not get up until the clock says X time?
If that won't work you need to child proof your home. I have a dog so there's no chance I'd leave a cake on a counter a five year old or a dog could reach, it would be on top of a cupboard or on the fridge. Ditto the plasters, my kids loved playing with those, so I started hiding them out of reach else they'd be stuck on teddy bears and dolls or in their hair.
Try involving her in your hobby. I think she probably just wanted to help. Five year olds aren't really clever enough to think 'Mum really loves this thing and I hate her so I'm going to destroy it'. If you teach her how to help properly and do it together, she's less likely to surprise you by making it pretty while you're not looking.
And do take a trip to your GP if you feel anxious or a teary a lot of the time. They are there to help and won't judge.
I hope you enjoy the rest of your birthday OP. If you can get to one, Tesco, Asda and the like often reduce birthday cakes after 8pm ish.