Change in vaginal discharge and heavy spotting for over a week PLEASE HELP

I am on birth control and take it consistently. I have been on it for several months now. I had sex with no condom, but my partner tried his best to pull out, but we weren’t too worried because of my birth control. The day after, I started having heavy spotting with no cramps or any other period pain. That was 11 days before my period was predicted to start. Now my period is predicted to start 3 days from now and the heavy spotting/light bleeding hasn’t gotten any better. Sometimes it’s brown-stained discharge, other times it’s pink or or pink with bright red blood in it. Along with the bleeding, I have gotten painful period cramps (pain in lower back and lower abdomen that spreads down to the front of my thighs) and headaches along with bloating and fatigue. I’m not sure what’s happening. Please help.