I take a shot of estrogen ever other week. A day or two before I should be taking my shot I get these splitting headaches and my stomach gets upset. The first time it happened to me I thought it was just a coincidence, but now it has happened three or four times in a row. It didn't happen to me when I first three months I've been taking the shot. As soon as I inject myself I feel great. I'm just wondering if this happens to anyone else. I'm going to bring this up the next time I see my doctor.