Concerned

So long story short, my hubby and I have been ttc for about 3 years now with no luck. I have been diagnosed with pcos and just recently have some what started to have a natural period but they come and go whenever they want; basically the past year I've only had like 2 periods. Well last Sunday we had intercourse and Thursday I had a period that lasted a few hours and was bright red with a blood clot about the size of a quarter and then nothing. I did have a little brown discharge starting about a week before which is normal before I get a period and I'm now having a light tan color discharge. Was that my period or was it implantation?! No I haven't taken a pregnancy test since I'm pretty sure it's to early to even pick up. Any advice would be helpful.