Toilet won't flush!!!?

Yuck, how embaring. Usually it takes a couple of go's to flush my loo, but this morning it won't budge. When I flush there's a bit of a "swooshing" noise and I can see water moving in the toilet bowl, but not enough to cause it to actually flush. I'm terrified of breaking the flushing handle and I know nothing about the inner workings of a toilet. Please help!!!!!