I too have had bleeding after DTD and like you was not due for another two weeks. However that two weeks is up and havent had any signs of AF. My mid cycle bleed wasnt heavy but lasted about 4 days and was enough for me to know it was there.
Now I am worried because although another baby is in our plans, its not just yet. Have had about oh I dunno 10 negative tests and even got a first response one yesterday and that was negative too but am not feeling safe just yet.
Why dont our bodies do what they are supposed to when they are supposed too? Save alot of stress wouldnt it?