What Are The Side Effects Of Emergency Contraceptive Pills?

I've been on oral contraceptive for 7 1/2 years now for hormonal in balances. I've never missed a period in my life since being on the pill. I have noticed slowly they have gotten lighter, and lighter through out the months. Then this month, NOTHING some cramps but nothing else Is this because of I've been on the pill for so long? Or am I pregnant? Is it bad to be missing a period?