2 days instead of the normal 7 days?

Okay, I believed I recieved my period a few days ago, which would have been on time, maybe a day late, which is usually normal. However, it lasted about 2 days instead of the normal 7. Also, was horribly light, as I normally have rediculously heavy periods, and this time I didn't have to use a tampon. I have had light cramping as if I am getting ready to start, and breasts are slightly tender, which would be normal for me as well. Now, I am also under stress with going to college full time, working 40 hours or more a week, finals coming up, and the husband just started a new job, so money is super tight, adding to the stress. is it just stress, or could I be pregnant? I took a test and it said negative, but maybe too early to tell? Thanks for your time.