I can not understand why you say that the tests were unnecessary. Do you mean that the tests showed nothing out of the ordinary? In that case, you should be glad for that and there is no reason for deep regrets.
About the risk of getting cancer:
A male of 22 years old has a baseline cancer risk of 44,9%, meaning 44,9% of the males of 22 year old will develop cancer somewhere during the remainder of their lives.
2 CT scans of the head, one of the chest and the pelvic fluoroscopy increase the risk to something like 45,17%.
The doses from chest-x-ray and dental x-rays are negligible compered to the CT scans.
So, your chances of developing cancer are a bit above baseline, but not much.
Really, there is absolutely no reason to think that your life is ruined from the examinations.
Relax and stop let this bother you. Sleepless nights and worrying are not healthy.
You're worried about nothing. It takes far more medical radiation than what you've been exposed to to cause any kind of harm, long term or otherwise. I would have no issue having what you had done if I were in your shoes. You are not in a high risk category. Medical radiological procedures are not Chernobyl.