Missed period....Help

Michelle
Hi <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> Community,
I have a dilemma...I have always had an extremely regular period (always comes on day 28) but this month I have missed it completely. I had all the symptoms leading up to "my period" like: headaches, acne, cramps and mood swings but nothing ever came. 
I moved from South Africa to the USA 10 months ago. I'm not sexually active and I don't have a gynaecologist here as it's just a gap year. I tried doing some research but the results were terrifying to say the least. 
Can anybody give some advice?