I found two cool Git aliases that will show you all the commits that have been made today or yesterday. It's a simple way to figure out what you accomplished.

Define the aliases:

git config --global alias.today "log --since=midnight --oneline --graph --decorate"
git config --global alias.yesterday "log --after=yesterday.midnight --before 0am --oneline --graph --decorate"

Then run it with:

git today
git yesterday

I borrowed the idea from Coderwall.