I took a benadryl at 11am and .75mg of klonipin at 1:30pm. it's 11:30pm and i can't sleep. can i take 10mg of melatonin?

Better not: melatonin would interact with klonipen, which has a long half life i.e it stays in your system for days, in addition the benadryl also interacts with both, those interactions would lead to CNS depression, ? respiratory depression and other untoward effects. Use sleep hygiene: warm bath,quiet dark room, no caffeinated beverages in the evenings, no TV, internet or smart phones 1 hr before bedtime