Period or implantation bleeding

So this last cycle I didn’t log ANYTHING smh so I’ve just been waiting on my cycle to hopefully come. Well, it started or so I thought this morning, but I only lightly bled for half the day and then the bleeding stopped? My cycle is normally every 21-22 days on the dot and it starts heavy full on. Each time I wipe, there’s light red like mixed with the urine but no blood. I did have unprotected sex a few times so its a possibility that I’m either pregnant or stressed. About a week ago, I had constant headaches and nauseous:/ I have dull aches and I didn’t even fill an entire thin pad today.... I don’t have my normal period smell either so I’m a bit worried.

Has this happened to anyone?