Even on the pill I experienced random light periods. And, as you say, you are dealing with more stress than usual right now, so another reason for a lighter period.
As long as you are religiously taking your pill, you should be fine.
If you feel the need, take a HPT to eliminate this little bit of stress from your life. That way you can focus on dealing with everything else you have going on without this hanging in the back of your mind.
Welcome to the forum!