I'm so confused

I'm not sure of what this is (trigger)

On Wednesday Aug 16 I started spotting light pink for three days the fourth day I passed this clot of some sort and then came heavy bleeding and cramping ... later on that day I passed another clot as shown in the picture ...Mean while I was still cramping which lasted for two days but I still kept bleeding until that following Wednesday Aug 23 .. I went to my Dr on Tuesday and he told me that I was having a miscarriage and which was kind of a shock to me because I never took a pregnancy test until I came to visit my Dr he took one and it came out negative and he also ordered a HCG test and the results came back 0.1 ... I'm nervous because this has never happened to me