I To A Couple Hcg Test To Conform My Pregnancy

I to a couple hcg test to conform my pregnancy order by my obgyn and I was two weeks and my levels were fine they were 33 and doubling but don't know the number they went up to a week later got sent to the er for bleeding no cramps bleed for four days and allitle clots got told my levels were at 19 and that I was having an incomplete miscarrage but my cervix were closed I'm confused I have had one child 4 almost five no complications was on birth control for maybe a year and a half then stopped taking it the depo shot is there any way I can get this cleared up alittle for me? And is there anyway I just had a period and still pregnant would that make my levels go down