Help please

I had unprotected sex with my boyfriend on the 24th, which we are trying to conceive, I believe it was my fertile week but I’m not 100% sure, this app said so but i know it varies and isn’t always right..! Well I started spotting (there was no need for a liner, pad or tampon) it was very light and pinkish, it was only when I wiped when I see it as well, and it only lasted the day and that was on the 2nd, is that possible implantation bleeding or something completely different? My period normally comes around the 10th lately it’s either a day of or a day or two late. What day should I consider being ‘late’ next week so I can be able to take a test? I’m excited but also don’t wanna get my hopes up.