I switched birth control in January and it took about 6 months for random spotting to end. Now I sometimes spot maybe for one day around the time I would ovulate if I was not on birth control? Could I still be ovulating! Does this mean I have a bigger chance of getting pregnant? I have never missed a pill and take it at the same time every day.

Among other things birth control is meant to prevent ovulation so if you're taking the pills at the same time every day than you have a REALLY small chance of ovulating. 1-5% chance as per most of the documentation that is included with most birth control pills. The spotting doesn't indicate ovulation. Spotting midcycle can be just that spotting, nothing more than a little blood is leaking out. Implantation bleeding isn't common and would require impregnation.

To sum it up. Mid-cycle spotting is common, even on birth control and doesn't indicate that it isn't working. Birth control is pretty reliable but there is still a REALLY REALLY small chance of pregnant. Chances are you're not ovulating.