Does anyone know who is bothered me?

I have never received a call exactly like yours, where they've asked if I was who I am, then hung up, but I've had them hang up right after I say "hello". If you are afraid, call your phone company and, if you can remember the time they called, ask them at the phone company if they would check your records to see who called you. They may be able to provide your with at least a telephone number of whoever called, maybe even a name. Explain to the phone company why you are afraid. They might have some further suggestions. Good luck to you.

I get a lot of strange calls, and I can see where this is frightening, but I wouldn't worry too much. As someone else said, you can try to put a trace on your phone, if they can do that in your area. If this is a cell phone, I'm not sure whether that can be done, but it can't hurt to ask. The best way to avoid things like this, is to screen your calls and not answer calls from "unknown" or unfamiliar numbers. They'll leave a message if it's important.