Miscarriage? 9 weeks - TMI

Ashley
Hi,
First I'd like to state that this post is probably a little TMI but I'm scared. 
I am 9 weeks and 2 days, from week 3/4 until week 8 I was experiencing extreme nausea and dizziness which has been slowly dying down since week 8 hit. I have also had bad constipation. The night before last I experienced some pretty painful cramping and ended up with diarrhea the next morning (yesterday), had more cramping yesterday and today resulting in diarrhea. So basically, I have decided the painful cramping was due to the stomach issues. 
Well, about an hour ago I urinated, wiped and found a dark clump on the tissue. Wiped again and there was some brown tinge, a couple minutes ago there was no discharge or tinge. 
Am I being paranoid? Should I be worried? I had occassional spotting weeks 6 and 7, but it was all the light brown tinge on tissue and nothing more. We had an ultrasound at 7 weeks and there was a heartbeat. I'm supposed to have another one next week. 
Hoping someone has some insight. Thanks!