Where's my period?

So my boyfriend and I are trying to conceive and I was taking my birth control very on again off again because of my migraines it was hard to not take it. Now that chiropractic care has eased themigraines, I stopped taking my birth control. I stopped taking it on the 14th of february and had a very light brown discharge from the 19th through the 22nd. I thought maybe it was an implantation bleed but when I took a preg test it was negative. Since then there has been absolutely no sign of blood. Before I stopped the bc I’d take it one day, and then not take it for two days. If I didn’t take it three days in a row, I’d start bleeding really badly. We’re still trying to conceive so I’m going to wait a week or two to take another hpt. Does anyone know any other causes for no bleed besides being on bc for a long time. It’s especially weird because every other time I’ve missed 3 or 4 days of bc I’ve bled badly, and now all of a sudden, nothing!