If the last time I had sex was January 13, would early pregnancy signs be obvious by now?

As you can see in the screenshot above is a record of my menstrual cycles (red) and sex activity (green). It has now been five weeks since the last time I've had sex and I just want to know if it's possible if I could possibly be pregnant. My last period was on January 19th which is just a week after I had intercourse.

The reason I'm asking is because last week while I was ovulating, I had some sort of brown watery discharge. Normally, my discharge ranges from the color white-yellow.. So another assumption I had was that I was just spotting. However, I rarely ever spot, so I've just been confused. A factor that can maybe be noted is that on the first day of ovulation, my boyfriend fingered me. Once pulling out, he found that his fingers were covered in blood. Could that be a reason why? Also, over the past five weeks, I had no sign of nausea.

I'm freaking out because I've been researching and Google has me currently convinced that I could be possibly "implantation spotting".. which is one of an early sign of pregnancy. But it also doesn't make sense to me because I received my period 6 days after having sex.

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Please keep the information in mind while you answer these questions for me:

-Is brown discharge or spotting weeks after/before your period normal?

-It's been known that a woman can tell whether or not she's pregnant two weeks after intercourse. Since it's been 5 weeks for me, without having noticeable symptoms such as nausea, fatigue, or cravings, wouldn't early pregnancy signs be obvious by now? Could I still be pregnant even without experiencing such symptoms?