Pregnancy Tests

Can anyone help me?
My Partner and I have only been trying to conceive for one month now but I have just missed my period. I took 3 pregnancy tests at home and all came out positive only with a very faint 2nd line. I booked in straight away to go to the doctors and she did a urine test that came up negative!!??!
I was whisked off to have a blood test and find out the  results tomorrow, but I was just wondering 1. Why would my pregnancy tests at home read positive when negative? Or 2. Why would the doctor’s test read negative when positive???
I have had many what I consider to be “pregnancy” symptoms – Tender Breasts, Missed Period, Terrible Cramps in my Lower Abdomen and  I’m extremely fatigued.
It’s very frustrating and I know all I have to do is wait for the results tomorrow,  but being a first time pregnancy I’m am a little nervous.  Can anyone explain???

[Beccabb]

Could they have been evap lines? But 3 prob would be a bit far fetched, I'd of waited a few days to go do the doctors to let ur hormone levels Rose, but it could have been that the doctors test wasn't as sensitive as the one u used at home

[Beccabb]

Rise*

[tinkerbell1124]

Those urine tests aren't always accurate. If you drink a lot of liquids before you went to the dr. that can screw it up. I'd say you probably are. Let me know what  the dr says

[mum2b_2010]

I just go the results from the doc... and i am pregnant!! so exciting thanks for the advise ladies :)