Can someone help?

I was just wondering if anyone has any similar experiences. And I apologize in advance for TMI.

Me and my Husband have been trying for baby number 2 for about a month now.

I was due on my period yesterday. However, late Sunday (3 days before period was due) night I started spotting which was really pink in colour.

Normally my boobs are completely sore all over, but only my nipples have been this time. Also, I'm always a heavy bleeder with intense cramps. But I haven't really had any cramps at this time. I've also had headaches, dizziness, and nausea. 

Over the past 3 days the light spoting has turned dark brown, stopped, and then started again, but never more than slightly more than spotting.

This morning I did a test. Both me and my Husband agree that there is a very faint positive line there. But since doing the test, the blood has stopped, and then now, it's come back again and is red in colour with a couple of teeny tiny clots, and it's slightly more than what it has been, but still not enough to need a pad or even show up in my knickers, just when I wipe.

Has anyone ever had this that have been pregnant?

I don't know what to think...