Starting a "period" on the 4th day of birth control pills. Is it possible?

So a few months ago I went through multiple faint positives over the course of 4 months yet had negative blood tests.. Received my darkest positive before my doctor had me start sprintec because my period wasn't coming. They wouldn't set me up for an ultrasound and the doctor had pretty much had it..so that was the last resort. Whelp..i did start, not even halfway through the first row of pills. Up to the bleeding I was getting horrid cramps that nearly had me doubled over, then it just started. I stopped taking the pills but was still having cramping a few days after. It felt like all of my muscles in my lower body were trying to force something out. After that the width of my stomach started decreasing but the weight stayed. I stopped getting positives until last month, but they were faint and now I'm nearly three weeks late. After my last experience it has me really weary so I'm going to try and wait it out till at least my SO gets here for thanksgiving or af decides to show up..