Plan b


My last date for period was last monday, july 6, then the next day tuesday, july 7, I had unprotected sex in the afternoon around 4ish . Me and my partner were nervous so he decided to buy plan b. He pulled out tho but we wanted to be safe. The next day Wednesday we met up after lunch and I drank the medicine within 24 hours. I was fine after I took it but 5 days later so basically yesterday monday, I saw some spotting. Does that mean the medication work and got my period or is that just a side effect? Because my next expected period date is August 2. Please help me I'm worried and I just want to know. Thank you