Hello. I Have A Question. What's The Chance My Girlfriend

Hello. I have a question. what's the chance my girlfriend can be pregnant? A couple days ago, we had sex for not too long. We had sex about less than 30 seconds. I had protection the whole time and wasn't even close to ejaculation. I don't think I was really excited to produce precum also. However after we had sex, the next day her stomach hurt. This is her first time having sex and I don't know of she wasn't use to having something inside her. Also she's stressed out so I thought that can be a reason her stomach hurts. Do you think she's pregnant and what's the chance she can be pregnant? thanks!