Help !!!:)

So I had sex, unprotected the first few pulls and then we got a condom, he didn’t finish inside instead we finished w a bj (sorry for tmi but it’s relevant). Six days later I threw up about an hour after taking my birth control and didn’t take a second since I was up north and only brought as many as I thought I’d be there for so I didn’t have any to spare. It’s now 5 days after the “missed” pill and I do skip my periods and so this would typically be the week post period. I’m having brown sludgy spotty discharge for the past two or so days, I just wanna know the cause/ if I can stop it !!! Plz help, thank you :)