So confused, please read!!

Victoria
I'm 4weeks 4 days, I confirmed with doctor with blood urine and ultrasound. The ultrasound only really showed the uterine lining which was 12.5 
I've been spotting for a week and I'm freaking out. Cramping off and on VERY MILD.  The first 4 days was strictly brown most of the time it came with what looked like EWCM but brown. Then the last two days it's been Brown Pink and Red occasionally. It's lighter in the Am and late PM. Does anyone have any stories similar where it turned out ok? They said spotting and light cramping is normal but I can't help but think miscarriage everyday which I'm at a high risk. But if I was in the miscarriage process since the spotting had been a week would I have a think lining still??