I had my period last month can I still be pregnant

Hello ladies,

I had sex on Dec 19 (we didn’t use a condom at first but for just a few minutes and then we used one and kept it until the end and made sure it hadn’t broken or anything) I got my period on Dec 24th and it was a full week as usual, I was supposed to get my period on Jan 24th but now I’m almost a week late, I have my usual period symptoms like breast pain, depression and acne, but no bleeding yet. Also (TMI) I realized there’s a kind if brown substance inside my vagina but I’m not having any discharges. Is this normal? Can you have a full, proper period and still be pregnant or sth? I appreciate your comments and help in advance.

Sending love❤️