Headaches?

I am nearly 6 weeks out from having had a sleeve surgery and everything is going well and I feel amazing except.... I have brutal headaches. I mentioned it at my 3 week visit and they said it may be lack of water/hydration. I admit I am not getting the suggested amount of water but I am drinking at least as much as I used to if not more each day. The headaches come very suddenly and it is fierce around my right eye. I am worried it may be something else but it only started happening after the surgery so I wanted to throw it out there to see if anyone else had a similar experience.

I am not a coffee or pop drinker so I don't think it is caffeine withdrawl or anything like that.... But I get them daily at least once or twice a day. They only last about 30-45 minutes usually.

Thanks for the help!

 Pain on one side is usually a migraine. Could be the change in weather may be triggering it.

I would talk to my family doctor about this. It is not a post op effect I have ever heard of.

So I happened to be seeing Dr. B today so I mentioned the headaches to him. He advised that it is not a typical side effect but just based on the timing with which they started (about one week post surgery) he would like to keep in touch with me about it. I am going to see him again in four weeks instead of the usual three month update I guess. He felt that it wasn't a migraine because I wasn't vomiting or getting blurred vision but he said to try taking just regular Tylenol to see if it helps reduce the pain. If not or if getting worse then I should get to the family doctor (which I am likely going to do either way) but if it helps I guess he will have more info for me when  I see him in about a month. Just a little update. Thanks everyone for the input!