Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for fainting, severe weakness, breathing difficulty, or other immediately life-threatening symptoms.
Most nonpregnant people do not need a test immediately after completing recommended treatment.
An early NAAT may remain positive because it can detect genetic material from dead bacteria.
Arrange prompt assessment for pelvic pain, new testicular discomfort, fever, or worsening rectal symptoms.
Seek urgent medical care for severe or rapidly worsening pelvic or abdominal pain, repeated vomiting, high fever with significant illness, or sudden severe testicular pain or swelling.
During pregnancy, pain with vaginal bleeding, shoulder pain, marked weakness, or fainting requires urgent evaluation because these can be signs of an ectopic pregnancy.
This follow-up is meant to find reinfection, not because the antibiotics usually fail.
Contact a healthcare professional for routine follow-up if symptoms do not improve, return after treatment, or if a partner has not been treated.
The article also says
A test of cure, which confirms that treatment cleared the infection, is recommended during pregnancy about four weeks after treatment.
It may also be considered when symptoms continue, medication was not taken as directed, or reinfection is suspected.
Because repeat infection is common, people treated for chlamydia should generally be tested again about three months later.
If that is not possible, retesting should occur when the person next receives medical care within the following year.
Every sign above is quoted from the sofidex article on Chlamydia. If you are not sure, err upward — it is always reasonable to be checked.