Could I be pregnant? Been sick!!

Pip • Baby dust to all you ladies ❤️
I've been off contraception for 6 months now, I always had a 34 day cycle but my past two cycles have been a 20 day cycle. Last period was the 17th, the past 3 days at night I feel extremely nauseous but tonight I've been sick. Just really don't feel well. Could it be I'm pregnant even if I had a period?