Getting Old!

Now I realize that at 26 years old it is laughable for me to say this, but I feel old lately. I have a theory that every child you have ages you at least 5 years, (mentally and physically) so that would put me at just over 40! There are a few things making me feel this way. First of all Justin is starting Kindergarten in July, and I'm not sure why, but I'm having a hard time getting used to the idea. He's gone to preschool for the past year and a half, but for some reason kindergarten feels so much more official. I don't feel old enough to have a school age child, and I don't like that Justin's growing up so fast. The other thing that's aging me is that I've had a nasty headache for over a week now, and it's driving me up a wall. I feel like a little old lady with all the pain medicine I've been taking, and all the sleep I require. The pain is right behind my left eye, and it's constant and throbbing. I'd appreciate any tips if anyone has experience with this type of headache. I've been alternating prescription motrin, and tylenol every 3 hours, and that barely takes the edge off the pain. The last time I had this kind of headache was about 2 years ago when Dawson was 5 months old. I'm wondering if it could be something hormonal that happens 5 months after giving birth?! Has anyone else experienced this?