This is probably because of the hormone increase in your body. Ortho Tri-Cyclen Lo is a triphasic birth control pill, meaning it delivers three levels of progestin and a constant level of estrogen (hence the three different colors of active pills). This can cause mood swings. You should try switching to a monophasic pill. This way, there will be a constantly equal level of both estrogen and progestin being delivered to your body throughout the month. The constant changing of levels might be messing with your body, and this could be a solution. Some common brands of monophasic pills are Alesse, Loestrin, and Ortho-Cyclen (not tricyclen).