Had a sexual encounter (no actual penetrative sex, just third base for lack of a better term) on the 15th, towards the end of my fertile window according to Glow. Exchange of bodily fluids was possible, but highly unlikely, and I thought I made sure to stay careful. Felt some nausea and I've been constipated (TMI, sorry) and breasts felt sore (normal for PMS), so I tested and got a negative at 3-4am today. Period was supposed to come yesterday and got nothing, but today I've had pinkish-light reddish discharge with a few tiny clots and cramps and a very small amount of blood on a liner I wore. I don't remember recently seeing anything like this before AF, but honestly, this is the first period I've really ever monitored this closely, so it's very possible that I've missed this light bleeding before. I'm gonna wait and see if I get anything tomorrow, and then maybe wait some more to test. Also, I did just get back from a four day vacation yesterday, so that could be having an effect on my cycle as well. I'm usually pretty regular at 29 days, but I looked back at my calendar for recent months and I saw that I've also been 30 and 27 days. Does this sound more like an early period or potential implantation?