If you had a kidney/urine infection it should have been picked up from your urine sample and you would have been prescribed antibiotics. Also, it's highly likely you would be feeling unwell with this type of infection.
Has your GP prescribed any medication for your high blood pressure?
High blood pressure can damage the kidneys and a symptom of this is oedema (swelling), but this could also be due to your weight. If you do have a problem with your kidneys, this will be evident from the blood test.
It could also be one of several other things and until you get the results of your tests there is no point speculating or worrying about it.
Does your GP's surgery have a hypertension clinic? If so, they will keep an eye on your BP. Just out of interest, was your BP reading done by your GP the same level as the one you took at home?