Not sure if it was implantation bleeding

So last week I had some slight bleeding. It was really light (it was less than my usual spotting). It happened for a couple of days on and off. I know I should have taken a picture of it so I could have added it to this post and maybe get a definite answer. The same days I had the bleeding I had some sharp pains in my uterus. They didn’t last long but I found it strange because I never had pain like that. My last period was from October 9 through 12. I did have unprotected sex right before and that period was lighter than normal. I have missed my period for November, but I also did have unprotected sex again in November before my missed period. I took a test in November once I missed my period but it may have been too soon. I do plan to test again but not until I’ve missed my period completely. According to eve, my period is to start December 16. I know the date eve predicts is not accurate (I usually start a few days before what it says), but I just rather assume that maybe it’s right this time and when it’s estimated days for my period pass then it’s time to take a test. I guess what I’m really asking is has anyone else that had implantation bleeding also have any pain in their uterus?