Positive thoughts

When I found out I was pregnant everything was going great , levels were going up quickly than normal.. then boom they dropped from 2077, to 1351.. then 588 and now yesterday they were at 98 . I should be 5 weeks and 6 days pregnant.. my ultrasound yesterday showed the gestational sac was gone and weirdly I had no bleeding or pains ... This morning some bleeding has started with light pains ... This will be my third miscarriage... I has my 2 sons with healthy pregnancies then a brighten ovum and then a chemical pregnancy, and then I was blessed with 2 daughters after with healthy pregnancies.. Its always in the back of my head , how can I have 4 healthy pregnancies and babies and still have miscarriages... I am extremely blessed with the children I have , its just losing pregnancies definitely has the depression sink in ...