Q about Dr's Pregnancy Tests

Ok so I went to the docs yesterday as I have a water infection and they done a preg test there and then and its just occurred to me that she looked at it and went its negative but she never waited 3 mins.

Are Dr's tests instant ones? it was actually the nurse but I explained to her that I had been getting faint lines I have poas since last week now as was just fed up with it all and it was costing me a fortune.

Thing is I know I have a water infection, but my stomach is so bloated, I have loads of gas I burp for no reason and they are loud and horrible, my boobs are still sore and i had a pain in the side of my boob this morning and am getting little niggly feelings in my stomach. Is this the water infection or do I still have hope??

Can having a water infection affect the results on a test or is that nothing to do with it as have looked on google and some say that it can put off a positive result if the infection is bad enough. My back is killing me, I feel like a pensioner!!

Its always so complicated with me!!

xx