Is it possible to get a very light tan/brown discharge the time you would've got your period?

Hi all, me and my partner went in for a scan about a week and a half ago and saw our wee peanut growing really well, person who did scan was really happy with way baby looked and the heart-beat. I'm now 9w4d pregnant. On Saturday I woke up and went to the toilet and wiped and my discharge was abit darker. Barely noticable but I could tell it was there. This was 3-4 days after we had sex. Sunday I didn't have any.. Then Monday I had abit more, and same with yesterday (it always seems to come after we have sex) As we did yesterday too and I didn't have any of the light brown discharge until after sex. It seemed like more but wasn't because I knew it was his c*m. I still have my normal pregnancy symptoms going on, do feel abit better today but it comes in waves, I've had no pink/bed blood at all since my period before I was pregnant and I've had no pain/unusual cramping. Have had the uterus stretching pains but they're barely noticeable and come and go every few days! I jus wanna know, could this be leading into a miscarriage? My partner thinks I shouldn't read to many things about it on the internet because I jus end up worried and scared! Could it be from sex? even if I didn't get the darker discharge until a few days later? Or could it be because this is jus after the time that I would normally get my period? Thanks to all who give advice, 10 points for most helpful answer :)