Yes, it is definitely possible that you could be pregnant.
The chances of you being pregnant depend on many factors including your fertility, your partner’s fertility, and where you are in your ovulation cycle. If your period was over one week ago and your periods are usually every 28 days then you are likely in your fertile window.
If you do not want to be pregnant you may want to think about buying Emergency Contraception at the pharmacy. You are still in the window of being able to take this. The sooner you take it the better, but it is generally effective up to five days after having unprotected sex.
If you are not ready to have a baby, then I also recommend you think about what method of birth control might work best for you. There are many options including birth control pills/patch, intrauterine devices, the Depo-provera shot, the implant (Nexplanon/Implanon), as well as more permanent options depending on your future childbearing plans. I recommend you talk with your physician about what might work best for you.