Calling a hotline is one thing you should never be afraid to do. Based on the situation that you just need to talk to someone (as opposed to actually committing or on the verge of committing suicide, in which case it would be a different call), here's what most likely will happen.
Usually a real person picks up the phone right away..generally, most hotlines don't have that automated computer "press 1" stuff - you get a real person. They'll tell you a bit about themselves, and ask you about yourself. But, they won't press for any identifying details about yourself if you're not ready to tell them, like your name or where you're from.
Generally, the helper will help you unwind and start to talk about what's bothering you. The length of this call can last anywhere from 5 minutes to several hours - but during that time, and any other time you feel sad or scared, there will be someone on the line waiting to talk things over with you.
Here's a handy dandy link to what to expect when you call a crisis hotline. Hope it helps. http://suicidecrisiscenter.com/whattoexpect.html
Take care, and don't hesitate to make the call that could save a life.