My clipping masks are creatinng blocks of transparency where a brush should be??

I have no idea why this is happening. I'm a student so it's really starting to frustrate me I can't do my work. I think it only happens on clipping masks since I opened a new file and tried drawing on a regular layer and it worked. I attached a video below because I'm not really sure how to describe this problem or how it even happened. I would really appreciate the help.