I can totally relate to how you feel. I went for a scan today (I'm 11 weeks). Everything was great - baby moving around, strong heartbeat. 2 hours later I had some brown on the toilet paper. I went from such a high to feeling more worry. I'm sure nothing too bad could have happened in that 2 hours since the scan, but even so, it is worrying.
It seems like we are at the same stage, so maybe it's the result of a bit of stretching going on?