Spotting

Sorry for the vague subject title but i'm not sure what to call this. I'm also new here, this is my first post.
I'm not sure what is going on right now. I finished my last period two weeks ago, around the 13th. I am on ortho evra and have been on that since march, and before I had been on orto-tri-cyclen for about 2 years. I've never had any problems with spotting or irregularities with my periods. I switched my patch on saturday, as I always have, but I had trouble getting it to stick this time, so I changed it as soon as I noticed this, only a few hours. Yesterday I noticed that I started spotting, light brown and very very light. This morning it was the same except for a piece of tissue I guess, came out too. I put a tampon in and went about my business and when I came home I had very dark bloody discharge. I've had minor cramping, a lot milder than I do when I have a period, and some lower back aches, not really pains, it's just been achy. Over the past few weeks i'd had some issues with eating, things would not sit right, they'd either go right through me or i'd get terribly nauseaus. I never really put these things together, still don't know if there is any link. I made an appt at my gyno, but can't be seen til wed. Does anyone have any ideas, i've never been pregnant before but could this be a miscarriage? Any input would be great, thanks in advance!