2 weeks off of BC

So I stopped taking my birth control about two weeks ago. I was on the mini pill since I was breast feeding. Decided to stop to start trying for a third kiddo. After a week we did BDing and a week later (today) I have very light cramping and my CM is pinkish very light pinkish. Not even enough to get on a pad, only shows up when I wipe. I thought it was start of period but could it be pregnancy? Can it happen that fast? AF never returned so I don't know what or when to test or think. Just in need of advice. Thanks momma's