Caffeine and Headaches...

Okay so normally I'll have one coffee and a few 5oz cups of Coke/Pepsi a day, never drank soda before I was pregnant now I always crave it... I've been drinking no coffee now and maybe 1 cup of soda a day if that. Usually I'd only drink 2-3 bottles of water a day I'm trying to drink only water now... But these headaches are TORTURE!!! I usually take 1 Tylenol extra strength (500mg) can I take 2 or no?