If your pregnant it should show up on a hpt but if you want to wait until maybe the 23 it would really show up.
I tested a few days before my missed period because I was peering alot and had a sick feeling in my stomach. I used First Response and it had a very faint second line, but sure enough I am pregnant. So, yes you can test now.
to add on * im going to th washroom more then usual .