?? I don't understand!!!?

Someone help me understand. I was on my second week of my second month of birth control, and I missed 3 days so I just stopped taking it completely because bf and I decided we do want to get pregnant I wasn't due for my period till 4/26. Before I stopped my BC I was feeling crampy, nauseous , vomiting , sore breast the whole 9. And I took a pregnancy test 2ce and both negative but today I had little to no cramps I just went to pee and I had spotted on my liner (SORRY TMI) AND when I wiped it was blood... does this happen when you stop birth control early??? I'm so confused -_-