A psa test by your GP shouldn't take long to come back. Just like any blood test you should find out within a week or so.
There are a few things you should make sure of before you go for the test, otherwise you might have a raised psa level that's not related to prostate problems.
My doctor told me not to ejaculate for a couple of days before the test as that can raise psa levels. Likewise no strenuous exercise or cycling two days before a test. And make sure you don't have a UTI infection or the results are void.
Its normal to worry but at this stage there really is nothing to worry about. Its just a blood test and nothing more.
Most likely the home test was inaccurate and you have no issues to worry about.