I need advice. Please help.

So my boyfriend and I have been dating for a month now, but we've known each other for over 10 years. We had sex for the first time over the weekend while I was staying at his house. It was amazing but he didn't wear a condom and I'm pretty sure he cummed in me... What are the chances of me being pregnant? My period is due in 6 days and everything I've read said you can't get pregnant unless you have sex when you ovulate, and some things have said that they got pregnant 3 days before their period was due.. I'm only 16 and he just turned 18. I want kids but I'm not sure if I want one this soon... I have a job but it's just $15 a day, and he's still in school until next April. Could I be pregnant or no?