Anxiety Recovery: Guilt over slip up

Hi,

I have suffered with anxiety/panic attacks for three months. After two months of near daily panic attacks, they stopped. I still have not felt 100% and a lot of things e.g. seeing friends, work were possible, but a struggle.

Last weekend I went to V festival, got drunk and had a little bit of cocaine. This triggered a panicattack that lasted most of the night. Ever since, my sleep has been the worst it has been for months, I'm stressing over the panic attack and feel guilty for slipping up.

Does anyone have any advice? I'm finding it hard to let it go.

Thanks,

Max