If you didn't receive full credit for your assignment(s) or you received a lower grade than you anticipated, first take a look at your Participation Report by clicking "View My Grades" on the left hand side panel, right below your name:
Here you can see your posting history as well as a breakdown of your weekly participation. At the top, you'll see your community's Next Deadline. Click Show Deadline Details next to it to see a full breakdown of your grading requirements. This is the criteria used to calculate your total grade for each post!
Double check that you've completed the required amount of posts (questions and responses) before the deadline, and that you've met the Curiosity Score minimum (if there is one needed). You can see the timestamp and Curiosity Score on the bottom left hand corner of any post.
If you still have questions or need further clarification on your grade, please contact your professor with any concerns.