I keep losing my points

Hi Pablo,

Khan Academy does not ever restart or reduce your course progress. However, there may be a couple reasons why your mastery percentage has decreased.

If you answer a question incorrectly on an exercise, quiz, or unit test after you have previously mastered that skill, your mastery percentage may decrease.

Additionally, we are always working to improve and expand our content library. When we add new content, your Mastery percentage may go down, since the overall number of skills available will increase (for example, instead of mastering 90 out of 100 skills, you'll now have mastered 90 out of 110, which would reduce your percentage from 90% to 82%). You'll still have mastered the same number of skills as before, you'll just have additional ones to complete now. 

I hope this helps! Please let me know if you have any additional questions!

Oh, that's kind of sad. But fair enough. I'm very glad for your help! 
It's a shame that that little percentage has to be obtained by doing the unit test again (i.e. 30 questions correct in a row). Well, at least I guess I'm learning. Have a nice day.