Nightmares.

I drink a lot of caffeine before bed and I think that might be causing me to have nightmares recently, I usually drinking caffeine before bed. I occasionally have night mares but recently they have been every night. My SO started working graveyards so I’m alone at night and I think that might okay part in it. My dreams have been really really weird and scary. How long before I go to bed should I not drink any more caffeine??