The way that stress affects your cycle is by causing delayed ovulation. This, in turn, will cause AF to arrive later than expected. It's actually a myth that stress will cause AF to be late. The time from ovulation to AF (the luteal phase)is remarkably consistent, usually 14 days for most women. If you did not ovulate at all during a cycle, then your may have an unusual AF, or no AF at all.
I think that many things have the potential to affect a woman's monthly cycle, including medicines, illness, extreme exercise and stress. For me, my cycle was never regular, always off a day or two. And once, while TTC, I skipped altogether and thought for sure I was pregnant, but was not and had to get an injection of progesteron to jump start my period. I had never skipped a period in my life, and we were trying so hard to get prego but did not and did not get my period either. Go figure.