So I recently had sex with my boyfriend it’s my third time doing it with him but after I had sex with him on the second time my left lower side of my stomach started hurting later when I went to the restroom it started to burn a bit when I pee, I have been needing to pee a lot also my back has been hurting !! He used protection and he also pulled out before he was about to come ! Can I be pregnant? Also I did throw up once

Please help me I’m only 16 I don’t need a kid right now!!!!