Implantation bleeding?? TMI

Hey girls. So I’m looking for advice here. I am not on birth control currently. Last month my boyfriend and I had sex on the last day of my period. We used a condom but it broke, so I took a plan B the next day. After taking the plan B I spotted for about 4 days. After that incident we have only had protected sex. Now fast forward, I am 4 days late for my period. I’m wondering if the plan B delayed my period, or if I skipped it all together. Or I could be pregnant. Yesterday while I was at work I thought I felt my period starting so I put a tampon in. Just had some red/brown spotting but nothing more. Could this be implantation bleeding? I’ve read that it’s not usually as bright red as it appears in this picture. But I’m not sure. If anyone has experienced this let me know! Oh also, I realize there was no reason for me to take the plan B while on my period however I am very paranoid so I took it for my boyfriend and I’s peace of mind lol🤣