I can't seem to relax when I go out to do something and there's a huge crowd.
Even when it's in cases of celebration, I'm always looking around and trying to see if anyone does something out of the ordinary. If someone is about to kidnap a stranger or "take out" a "target," then I'd want to be alert so I can try to get away or go get help if anyone is armed. Whenever I'm with friends or family, I just feel like I have to try to protect everyone because they're not paying attention to anyone who could be creeping on us or stalking from a distance. I think too many video games and movies have shown how easy it is to creep on someone out in public without being noticed because you ignore most of the stuff you see in front of your face these days. At the end of the day, you've forgotten most of the strangers you've seen and most of the random names you've heard.
Does anyone else ever feel this way or am I just being paranoid?
I value my life too much to just let some criminal catch me off guard and take advantage of the situation.
Yes you definitely sound paranoid. It's not normal to scan for stalkers or attackers whenever you're going out. There are certain situations where you may be at risk, such as walking around a dark and isolated area, train stations, or around people who are drunk (sometimes they get violent and try to glass people). But on the whole the risk is low most of the time.
You do sound a touch paranoid. But this could also be anxiety/PTSD. You seem focused on threats and potential threats which is abnormal behaviour. See your doctor about this issue.