Help!!

So my last period was April 5- April 10, my projected ovulation was April 21- April 27 with the 26th being the highest. My husband and I had sex on the 25th and we were being careful and using a condom but it broke! So like 10am on the 26th I took a plan b. I know that it works best within the first couple hours but it was the middle of a storm at night so I couldn’t leave. I am over the recommended 165 and I think I had ovulated. My next period isn’t supposed to start until May 10th but I have been cramping the past couple days pretty bad. We had sex last night and now I’m bleeding but it’s like brown and kinda pink. I have never taken a plan b before so I have no idea what to expect. Should I still watch out for being pregnant or can it really make my period start this early?? Please help.