vasectomy help!

So my husband had a vasectomy last year. He returned for the sperm analysis and was given the all clear. Before he had a vasectomy we had a daughter, I knew before I had missed my period that I was pregnant. I felt so sick and just ill, ended up having hyperemisis the whole pregnancy. It was awful. Anyway, so now I am having the same feeling. I have felt unwell for the last couple of days and I have only felt like this when I was in early pregnancy before. My period is due in 2 days. Have any of you ladies had a partner that had a vasectomy and then ended up pregnant? If so did he have the sperm check and get the all clear? I know it is the tiniest chance but it isnt impossible...