Brown spotting with little pieces of tissue after pap smear

I am 6 weeks and 4 days pregnant today. I had my first doctor's appointment yesterday and they did a pap smear. My doctor said I may spot and that it was totally normal. I didn't have any spotting until this afternoon I noticed some light brown on the toliet paper when I wiped. I wasn't too worried but tonight I noticed there are what looks like little pieces of tissue. I am terrified as I have had 2 previous miscarriages and my last one started with brown spotting. I did get to hear and see our baby's heartbeat yesterday, a strong 120 bpm and measured perfectly. I just know it only takes a moment for something to go wrong. Has anyone else experienced this? Thanks