don't force it! sometimes it just never happens because our brains aren't wired that way. try your best but don't lose too much tears over it (although a cleansing cry is always great!)
omg u sound like me when im doing online school work. i feel u.
perhaps try watching a tv series u like, take a nap, or drink some tea? (or just anything calming) listening to music also seems to calms me down. i hope it gets better.