20 weeks 2 days! how often can feel baby movements

Hi all, now am 20 weeks 2 days the day before yesterday I had some movements I could feel heavy moments of my baby but yesterday I didn't much and today I didn't feel at all is that normal waiting for my scan on 8th but still am worrying lot n thinking searching too much on it pls help anyone, this is my 1st pregnancy.how often should we feel movements on 20th week? Help me pls