Could Going Off The Pill Give The Symptoms Of Pregnancy?

I am 40 years old. I took the pill (Mercilon) last Apil-July then stopped.I again took the Mercilon pill for 13 days (Sept.30-Oct 12) then my husband and I decided we perhaps wanted to get pregnant. Since stopping the pill I feel pregnant; nausea, aching hips, clear discharge, exhausted. We had sex when i went off the pill. I took a pregnancy test and a blood test which both came back negative (although it has officially only been 2 weeks since being off the pill). Can going off the pill give me all the symptoms of pregnancy or can a pregnancy test that says it can detect up to 4 days before a period be wrong?