First of all don't beat yourself up about it. Everybody makes mistakes and it's better to provide a strong role model as a parent by accepting your mistakes and learning from them.
I would recommend that you do consider taking her to her GP but try not to phrase it as 'you wet the bed therefore there must be something wrong with you'. Some of her behaviour do fall into symptoms of depression but obviously it really needs a GP to diagnose.
In the meantime, try to cut out the shouting, make sure that she eats healthily and gets some exercise. Show her that you feel that she is worth bothering about. Treat her to running a bath with lovely bubbles/salts/smells/candles or take some time out to listen to her or play a game etc.
You should be aware that depression can affect concentration (the homework that took ages), memory (forgetting anything and everything), sleep patterns, etc.
Before she gets told off for forgetting things (something I was terrible with when I was depressed) please try and remember that she didn't do it delibrately. She perhaps has a mental block about these things and the harder she tries to remember, the worse it gets. Particuarly if she is in trouble over it or is humiliated by it.
Part of it is ofcourse that if she is depressed then she won't feel that loosing her things is important - her self-esteme is too low to make an effort for herself.
But please please please cut out the shouting, if nothing else. There are always better ways to deal with things - my memories of being shouted are my strongest ones of childhood, I can't emphasise how awful it is.