Please do not worry! you can easily gain your modules back to your account.
On the left hand side of your dashboard you will find a grid, these little boxes are the modules you need to complete in the course.
if you have taken the filter, this will grey out some modules and the little boxes will turn grey. if you wish to reverse the Filter just click on the grey module, like this.
This will then take you to the module you have filter out. select "FILTER MOFULE IN" and this will automatically put the module back to your course.
You may now continue with your learning!