How long have you been doing this? I've had a hard time falling asleep my entire life (no issues once I am asleep). I'm resistant to chemical solutions, and I think my sleep issues are more emotional, given that I can fall asleep early if I really have to, but I can only maintain it for a week or so. But after a life time of laying awake, I am curious.

Math before bedtime used to cause me sleep issues. Not sure if you tried doing it early in the morning or not, but also your bed should only be used for sleeping (sleep hygiene) and nothing else (no math)