What Causes Dizziness And Nausea While On Birth Control?

i just started birth control about 2 weeks ago. my boyfriend 2 days ago put his dick in and we had sex for only about 5 minutes and he pulled out because he was scared he would cum. im scared he might have leaked some cum into me when he did it because he leaks sometimes. it has been 2 days and im dizzy and feel kinda sick. could i be pregnant or is it just symptoms to my birth control?