What is going on?

Ronda • TTC #1 since Sept 2013.
So I have an appt with the gyno next Tuesday but I'm trying to figure out what is going on and seeing if I can get insight. 
I'm on CD43 in a cycle that is normally 28-30 days and I've never been late like this. Over the past couple of days I've been spotting lightly. Now nothing. The last hpt I took was Saturday and it was a bfn. I've had two MCs and both times I had a positive at CD 29 or so. 
Anyone have any insight. This is just weird.