Spotting after sex?

So I am 6 weeks 1 day today and I just woke up and went to the bathroom and I had some spotting again. My husband and I had sex in the afternoon yesterday and then I have this spotting at 4 am could that be why? It's really light spotting too I have had this before at 5 weeks 2 days they said its normal and nothing to worry about but naturally I am worried and I was wondering could it be from the even tho it's so far apart from when we had sex? I have an appointment with an ultrasound today at 11, should I just wait for that since it's just spotting and not a flow or should I go to the er now?