Late Period! HELP!

So my last period was March 13 & this month I still haven’t started. I have about 4 apps to track everything for me and they range from 6days Late-8days late. I had sex with my husband on the 31st of last month. App says 2-3 days after my ovulation. I’ve taken 2 First Response test & Both came out Negative! So I called my doctor and she said to give it until next week to see if I start and if not to go get blood drawn, because it’s still too early to do a blood draw right now. I guess I don’t have much HCG. How high are the chances for me of pregnancy? PLEASE HELP!