Can anyone help? Xx

Aimee
AF was due 27/3 and i took a hpt the following day (28th) and got a bfp. I tok two more tests that day, all were positive (including a clearblue digital which said 1/2 weeks pregnant). I also did another test when my period was 1 week late (3/4) which was positive.
On Sunday night i started bleeding quite heavily so went to the urgent care centre. (At this point, Glow told me i was 5 weeks and 3 days). Doctor there did a urine test and said it was negative and that i'm not pregnant. My partner and i asked if i'm having a miscarriage. He said 'i doubt you were pregnant, this is probably just your period'. 
I'm really confused as to what is going on. Was i ever pregnant? Or am i miscarrying? 
My bleeding is extrmemly heavy and i'm passing lots of clots (which i never do during AF). 
I'm booked to go have bloods taken this afternoon (they were booked before the bleeding) and i'm worried that the results will confuse me more! If i am miscarrying would there still be traces of the hormones in my blood? 
Sorry for the essay i'm just really confused. I think i know in my heart that i'm having a miscarriage. I was definitely pregnant. 4 positive tests.. Surely they cant all be false positives? 
Has anyone else experienced anything like this? Xx