There are many psychological reasons a child starts bed wetting, some innocent and some sinister.
Please take her back to the GP, let her talk to the GP or a trusted medical professional alone.
It may be something lke being bullied at school, something she saw that's upsetting her, maybe she has night terrors too
The first thing - which is really really hard - is put aside your anger. Let her know that you are not upset or angry and that you will help her work through this. Teach her to strip her bed and leave the washing machine open at night so she can put the sheet and pjs straight into the machine. Explain she has to have a quick shower every morning.
Ask her if she'd like some pulluos until this is worked through. Once she is assured of your support, it will be easier to deal with the underlying issues - medical or psychological.