What Causes Vaginal Spotting While Trying To Conceive?

My bf and I are trying to conceive. I missed my period in September. This month I had spotting for three days. It was very bright red and had no period smell. It was nothing like my period and wouldn t have filled up the pad if left on for the entire three days. My pregnancy tests are negative but I definitely feel pregnant. I have been sick a lot. My period is always tge same and i know exaxtly when its going to come on. This spotting was 7-10 days before it should come on. I have never had this happen until now, after sex with my bf. If you re not registering any hcg, what would you recommend me doing?