Question about Aligators at hilton head beach?

Ill be going to hilton head South Carolina beach and if I saw an aligator or shark on the beach or in the ocean with me I would probably just drop dead out of fear...

Anyway, I'd like to know before I get there how common aligators are on the beach, baby aligators, large ones, all of them. Have you ever seen one on the beach? What on earth would you do if you we're swimming in the ocean and you saw some aligator eyes looking back at you? They are much faster than you so unless they aren't hungry?

As for sharks, I've read the water is really murky and that there are probably small sharks swimming right next to you and you wouldn't even know..... Is that true, I mean, how common are shark attacks/bites?

I know I'm probably being a little overly paranoid but if I'm going to swim with this stuff... Lol, so thanks in advance for any answers ;D