Your period isn't always going to be the same. Sometimes you'll get the same old PMS, sometimes you won't-- there are other factors that can affect your period, your cramps, and just about anything else related to your menstrual cycle.
You've been stressed out of your mind lately, that's enough to affect both your period and how painful your cramps are.
It sounds like you got your period and you're not pregnant. If your cramps are unbearable and over the counter medications like midol, advil, or pamprin don't help at all then go to the doctor to make sure everything is ok.