Stress can definitely affect getting pregnant as it can negatively affect hormones and all sorts of things however after 2 years, I agree with the others and think its time to see if there is anything else going on.
Stress affect your period and chances off pregnancy .
This first time iv had a strange period x
Stress can do lots of things to your body. if it has been 2 yrs you should contact your dr as there could be more going on