This app was mentioned in 3 comments, with an average of 1.00 upvote
Try Big Days.
https://play.google.com/store/apps/details?id=com.astrovicapp.bigDaysLite
Can't attest to how good it is, or the presence of widgets, but it has the since/until countdown according to a list I found.
Or try The Day Before.
https://play.google.com/store/apps/details?id=com.aboutjsp.thedaybefore
It's mentioned as having a widget and the features you're looking for.