Spotting and blood clots

I spotted at 11 weeks very briefly so I didnt tell my dr. Now I'm 13 weeks and spotting again. This time it lasted a day and a half. Brown blood, sometimes with tiny clots in it. No cramping. No reasonable explanation for it. Just heard the heartbeat at my checkup yesterday before this had started. Dr didnt do a pelvic exam at that time. It has stopped for now. I thought it was no big deal after researching on the internet. But what's taking me by surprise is my drs office reaction. They insist I come in right away on Monday and squeezed me in and double booked me with another appointment. They say I absolutely need a physical exam, hcg level check, and possibly an ultrasound. They said any bleeding in the 1st trimester is a possible miscarriage and is not that typical. They just took it way more seriously than I expected I guess.

Anyone else experience this? Anyone else pass blood clots? Did things end up ok?