I Was Intimate With My Husband In November And December,

I was intimate with my husband in November and December, and taking birth control everyday. I stopped when my cycle began in early December. In January my cycle was late three days, and I had some symptoms of pregnancy (nausea, fatigue, headaches, changes in appetite). I also had nipple discharge. My cycle began in January, has come exactly 28 days later in February, and exactly 28 days later in March without being on birth control. I still have nipple discharge. There have been no positive home pregnancy tests. Is it possible to still be pregnant? I also notice daily feelings in my lower abdomen that I attribute to being gas.