[Adam the Fish]

Hey Nika,

This is exactly true - many things which induce hormonal anomalies (including stress) can cause your period to change, or just not happen at all.

At this stage, I shouldn't be too worried, although you can always take a pregnancy test if that's what you're worried about, and it will clear up any ambiguity.
If you continue to be worried, you can visit your GP too, but it's most likely to be something that you don't need to panic over.