[Affinity Designer for iPad Keeps crashing while working]

Hello Everybody..

I bought the app yesterday from the iTunes and I was thrilled with its powerful tools and it was a dream came true

but not for too long, I was making a project and suddenly the app quit and when I opened it again there was a huge steps that I made hasn't been saved in the document

I feel very frustrated and I don't know what to do.. does anyone know what to do?