Hi,
It’s always a good idea to seek proper medical advice when you have had contact with an infected source. If you had you would have been tested and treated.
Anyway, your test. Inserting the swab further in your anus would not effect the accuracy. Nor would fecal matter on the swab.
The test for Gonorrhoea is a NAAT based test and is incredibly sensitive, it only needs a tiny amount of bacteria to turn positive. You would have collected enough with the swab on its way out.
In other words your test is conclusive. You have not got gonorrhoea in your anus. Which is not surprising as condoms are excellent protection against gonorrhoea kudos for using them.
Do you know where your partner tested positive? Was it throat, anus or penis? As this makes a difference?
Wherever it was if you did oral sex on him, I recommend you test your throat and if he gave you oral sex test your urine.
Hope this helps, here for follow ups if not clear.