On creating a new post, instead of choosing 'Create a Post' you select 'View Drafts', like in the image below:
The most recent draft for the latest post as well as drafts for your other unpublished posts are there, unless there was an error when PeakD tried to save them.
You can also save a draft yourself, by clicking on "Save Draft" button at the bottom of a post while you write it (it turns into "Saved" after it's saved, regardless if you save it or it's auto-saved).