Confused:(

I m/ I was 8 weeks pregnant. Two days ago I started having mild cramping which increased my pain very next day and included abdominal pain & legs pain. Yesterday, my pain was really bad like I am starting to have my periods. Then I saw brownish d/c which after an hour changed to bleeding. I wouldnot say it was heavy bleeds but it started to look like the bleeding I have for my periods. After half hour, the pain was gone and so as the bleeding. In the morning I went to see my doc and told about my situation, and she did an internal scan in which she didnot anything in my uterus. She said there is no baby in my uterus😞 Could it be a ectopic pregnancy? Did i have miscarriage? I m really sad and devastated!! :( 
Then i had my HCG levels through my blood test and it came 138.5 which I believe is less for being 8 week pregnant. Doctor said there is like 10 percent chance that everything is fine and it could ne Delayed Pregnancy!! Any thoughts???