I know that it can be very stressful sometimes when we don't know what it going on with our bodies. Unfortunatly, I can't be of much help. You mentioned that you switched from Depo to oral contaceptives. How long ago did this occur? I do know that if you are on a low dose pill, they are known to give you shorter lighter periods. Some women (over time) can even stop menstrating all together. Have you had any lower abdominal pain or discomfort? I have had a large ovarian cyst before. It stopped my bleeding altogether. (that is how I was diagnosed) Although I don't know if there is always discomfort associated. I would seriously suggest that you contact your Dr and discuss your concerns with them. While it may be nothing at all, its always better safe than sorry.