New birth control & irregular bleeding

So previously I was on Sprintec, due to not being covered by insurance i stopped taking birth control and tried The Pill Club, due to having High Blood pressure in the past they recommended a new pill with no estrogen. I decided, why not, it's my second week on this pill and I've been bleeding for a few days now. It's a very dark brown almost black kind of blood and I'm genuinely concerned. I've reached out to the Pill Club but no reply. Has this happened to anyone else? I need advice. Please and thank you.