Hello. i missed three days of my birth control pills (ortho tri cyclin lo) and took two pills a day for three days. what should i do?

Use a back up method: If you missed 3 of your active birth control pills - it is enough for your body to start developing a follicle, so you are at risk of conceiving. I would recommend using a back-up method of bc for the next month, and consider using the over the counter "plan b" if you have had intercourse in the past 3 days, just to be safe.

Reset: While you might get away with this if you are near the end of your pack, you need to assume you are not protected. Stop the pill for a week and then start a new pack. Use backup contraception (a condom, for instance) for the next month. If remembering pills is a problem you should consider the ring, the patch or switch to an implant or an iud.