My chlamydia/gonorrhoea test came back inconclusive, what does that mean?

= not sure. In general: It is a very rare test that is 100% certain.For some tests, we use studies to set criteria for what is considered + or - ,based on comparison with a "gold standard" test that might be impractical to perform in the real world.Sometimes it can be inconclusive, which means it was in an area of overlap between + & - . In any case,a disease in an early stage may give inconclusive findings.
No definite answer. This means it is not clear whether you have either. Get tested again. Do not have intercourse if you are having any symptoms (discharge, pain, burning with urination). Use protection from now on after this is squared away, and save yourself a lot of grief. There are worse and permanent nasty diseases to get besides these two diseases, too. Be safe!