New to birth control I want to know if this is normal

I had unexpected sex with my boyfriend and we didn't have condoms and we used the pull out method I also took a plan b pill and started birth control. It's my first month of birth control and I'm taking my sugar pills but my period hasn't started and it's been two days is this normal and should I start taking my next pack since my period isn't starting. I also took two pregnancy tests and they were both negative.