I stopped birth control last month, and according to ovulation tests I still ovulated on schedule. My husband and I had sex twice during ovulation and soon after I had certain symptoms of pregnancy (nausea, headaches, fatigue , etc). About a week after ovulation I produced a large amount of discharge, so I assumed it was implantation . However, I took a few pregnancy tests and they all came back negative. I am now 4 days late for my period, which never happens, even without birth control. Could I still be pregnant? Or can something else cause these symptoms?