still mind baffled as to what's happened. have I had a chemical pregnancy or was I even pregnant?! help please.

Charlotte
So as you know people who have been reading my story about what's happened I'll up date you again, basically all last week I took clear blue plus pregnancy tests and they all come back with faint lines but they got fainter each day, so I decided to go to the doctors last Friday and showed the doctor my tests, he said I was pregnant but I explained to him that I took a digital the day before and it said "not pregnant", he looked confused, so he booked me in for my urine sample and a blood test for the next Tuesday which was this week...
Well after leaving the doctors and he told me the words "you're pregnant" I was so excited but still in two minds, well I started bleeding like a period, but a heavy one, so I called the doctor back up and he told me I was having a miscarriage and I was 7 weeks, so I was so so scared, in distress and an emotional reck.
So I had my bloods and urine tested on Tuesday, I had the results back yesterday, to be told the pregnancy test they did at the lab was negative and my bloods were also negative... So why did 4 pregnancy test at home come back positive?! I am so confused about what's happened. So did I have a chemical pregnancy or was I never pregnant in the first place?
Please comment and put what you think?