Switching BC and no period

MamaBear3 • I’m not like a regular mom, I’m a cool mom.

So I had stopped taking my birth control for a couple weeks over a month ago. The pill I was on was making me crazy. So I switched at the end of March. Now I was supposed to start my period 3 days ago, and haven't. I'm like clock work so this is odd. I've taken a few tests that have been negative has this happened to anyone?