Late Period

Hey ladies..so I was scheduled to start my period on Monday. For about 2 weeks I've been feeling a bit off. A little cramping here and there. It was stronger on Sunday so I thought it was because I was supposed to start my period Monday but when Monday rolled around there was no period. So then Tuesday rolled around and still no period. It's Wednesday now and I've already taken 3 pregnancy tests Monday and Tuesday combined. All 3 were negative. What do y'all think I should do? I love this app when it comes to tracking my period but when I put that I didn't start when I was supposed to it just moved my period start day to Friday? I wish it had a different option telling me possibility of pregnancy or something. Now I'm confused should I wait until Friday because what if Friday rolls around and I enter that my period still hasn't started? Will it move my period start date to another day again?