Tetanus shots really aren't bad. I've never been afraid of shots, though. As for the "do push-ups" afterwards, do it. My doctor told me the same thing a few years ago when I got the shot and I did, woke up the next day with no sore arm or bruise like many people talk about. As far as the hook sticking you, don't worry about it. Just keep it clean and keep an eye on it. For the future if you ever get hooked again - do the same. Keep it clean, keep an eye on it, and don't stress over it. I think one of the main reasons you were getting headaches was because you were WORRYING about the puncture so much. Stress and anxiety can throw your hormones off like crazy and cause weird symptoms like headaches, stomach aches, even nausea and hot sweats. WORRYING is something you don't want to do. I know this because I've suffered with anxiety for a few years now and when something goes wrong, the best thing you can do is look at it logically and be calm about it.