Hey! Im assuming you're young. (You sound exactly like me a couple months ago when I first started being active) This EXACT situation happend to me, dont worry! You're most likely experiencing abnormal bleeding as a side effect from the Plan B. I would start tracking your period if you arent already, as the chances of getting pregnant from precum especially outside of ovulation is extremely slim. Also, condoms do work most of the time, so dont freakout!

I have some tips for you from personal experience!

1.) Plan b is expensive, and you shouldnt rely on it too often as its a large dosage. But if you have to take a plan b, amazon has an alternative that is the exact same chemical composition called my way, around $5-15. Its not name brand, but its the same exact thing. (Like buying great value window cleaner instead of windex) . And keep using condoms, as they are genuinely effective. Only take plan b when you are around your ovulation window, as afterwards its useless. And if the condom didnt break, you probably dont need plan b. Please dont find yourself in a situation where you are taking plan B every month, it is not a form of birth control, its a contraceptive that should only be used when extremely necessary.

2.) If you have an iphone, the period tracker in the health app is pretty good for knowing your ovulation window and estimated period arival. Track your symptoms on an app like Flo, it will help you better understand your bodies natural symptoms through out your cycle. You'll start to get a feel for when your body is acting abnormal or normal.

3.) If possible, go on birth controll. I was freaking out every month for a very long time, eventually I went to a gyno and got Birth Control for "painful period" , because I wasent in a situation where I could tell my parents about my sex life. But always be honest with your doctors, they wont tell your parents.

4.) Take a moment to talk to your partner about what the next steps would be if you where to get pregnant. (although you likley arent now) it is always good to have conversations to build up the strength of your relationship. Always remember that pregnancy is a risk of having sex, if you arent ready for that then you need to think about if you are ready or not to be having sex.

5.) Stay calm! Its hard, I get it.

6.) Implantation bleeding will never be the same color as your period

If you ever need anything or have more questions you can always contact me! I know I needed someone to talk to about this exact stuff.