Caffeine Withdraw
Headaches from caffeine withdrawal is probably the most common side effect of doing this. As Celion said, it's very important to WEAN yourself off as gradually as possible. But I also still got some minor headaches when I was going off of caffeine, and like you, just used some ibuprofen to help with those. You're doing good, and good on you for getting off the caffeine!! 

Hi lynnier, just wanted to thank you for being the first to respond to my new member status. I have also been cutting down on coffee this past week. I do get headaches here and there. everything I have read basically says drink lots of water and after some time these headaches will pass. we'll see. I have such a difficult time even imagining not drinking coffee. I'm down to about 20% caff. coffee and the rest decaf for this coming week. Except for one year in 1997 I've used caffeine for 25 years. I do know that it DEFINATELY increases my anxiety which is worse than a headache so the caffeine has to go. I am thinking about trying to drink an alternative like yerba mate tea or ?.