Are there any health risk to taking 6 benedryl everynight to get a good nights sleep?

Wow: Please don't. Excessive doses of anti histamines will cause you increased risk for hypertension, tachycardia, abnormal irregular heart beat and render you completely brain dead for hours upon awakening. Please do not take that much benadryl (diphenhydramine).

Yes: It's possible to have what's called anticholinergic side effects, which can include constipation, dry mouth, wheezing, confusion, blurred vision, rapid heart rate, and difficulty urinating. It sounds like you're having a great challenge with your sleep. Please see your primary care doctor for an evaluation so he/she can recommend next steps. Hope this answer helps.