I think I might be expecting

This is my first post I'm freaking out I had my iud taken out on the 27th of February and had sex the day after and the last day of my period so I'm not sure what todo because I'm already 7 days late including this week I keep track of my periods onto apps this one said I should have started last Sunday and the other says I should have started this week but I haven't I took two tests last week around the middle of my supposed to be period Day but it came out negative should I be worried I plan on going to the doctor this Friday to check.